Arthri-Flex (glucosamine/msm/collagenII/hyaluronic acid/antiarthritic no3)

No dosing information is available for this tab.

No dosing information is available for this tab.

No dosing information is available for this tab.

No dosing information is available for this tab.

There is no enhanced messaging for this drug.

Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

Anticoagulants; Antiplatelets/Mifepristone

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Anticoagulants may result in excessive bleeding following the abortion.

CLINICAL EFFECTS: The concurrent use of mifepristone with anticoagulants may result in excessive bleeding following the abortion.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: The manufacturer of mifepristone states that mifepristone is contraindicated in patients receiving concurrent anticoagulant therapy.(1) If concurrent therapy is deemed medically necessary, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug.

DISCUSSION: The manufacturer of mifepristone states that mifepristone is contraindicated in patients receiving concurrent anticoagulant therapy.(1)

Aspirin (> 325 Mg); Salicylates/Dichlorphenamide

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Dichlorphenamide may reduce blood pH, causing a shift of salicylates from plasma into tissues (eg, central nervous system).(1) Alternatively, toxicity may be due to salicylate-induced displacement of dichlorphenamide from its protein binding sites and inhibition of renal tubular secretion.

CLINICAL EFFECTS: An increase in the pharmacologic effects of salicylates with possible toxicity may occur. Anorexia, tachypnea, lethargy, and coma have been reported.(1)

PREDISPOSING FACTORS: High doses of salicylates, low body weight.

PATIENT MANAGEMENT: The concurrent use of high-dose aspirin or other salicylates with dichlorphenamide is contraindicated. If it is necessary to administer a low-dose salicylate concurrently, use the lowest dose possible or replace it with a non-salicylate anti-inflammatory agent. Monitor salicylate levels and serum bicarbonate concentrations, and monitor the patient for symptoms of toxicity. Adjust the dose as needed.(1)

DISCUSSION: An 8-year-old boy with unimpaired renal and hepatic function was found to have developed metabolic acidosis after treatment for glaucoma and joint pain with a combination of aloxiprin 3.6 gram daily and dichlorphenamide 25 mg three times daily. His symptoms resolved after discontinuation of both aloxiprin and dichlorphenamide and did not recur on subsequent therapy with naproxen and dichlorphenamide.(2) A 75-year old woman taking dichlorphenamide 100 mg to 150 mg daily for therapy of glaucoma and high doses of aspirin (975 mg 4 to 5 times daily) for arthritis developed severe acid-base imbalance and salicylate intoxication. The patient did not exhibit ill effects when taking high aspirin doses without dichlorphenamide.(3)

Nsaid; Aspirin (>300Mg); Salicylat/Ketorolac (Non-Injection)

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Possible additive or synergistic side effects.(1,2)

CLINICAL EFFECTS: Concurrent use of multiple doses of ketorolac with other non-steroidal anti-inflammatory agents (NSAIDs), salicylates or aspirin may result in an increase in NSAID-related side effects such as bleeding or renal impairment.(1-3)

PREDISPOSING FACTORS: Patients with pre-existing renal impairment may be at an increased risk of adverse effects from this interaction. The risk for bleeding episodes may be greater in patients with multiple disease-associated factors (e.g. thrombocytopenia, advanced liver disease). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g., anticoagulants, antiplatelets, corticosteroids, selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs). Risk of GI bleed may be increased in patients who are of older age, in poor health status, or who use alcohol or smoke. Risk may also be increased with longer duration of NSAID use and prior history of peptic ulcer disease and/or GI bleeding.

PATIENT MANAGEMENT: Manufacturers of ketorolac state that concurrent use of ketorolac with either other NSAIDs or aspirin is contraindicated.(1,2) If concurrent therapy is deemed medically necessary, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory tests (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Conduct periodic monitoring of renal function, especially in patients with renal impairment. Instruct patients to report any signs and symptoms of bleeding, such as unusual bruising; red or black, tarry stools; acute abdominal or joint pain and/or swelling.

DISCUSSION: Based upon similar pharmacodynamic effects and potentially cumulative risks of serious NSAID-related adverse events, manufacturers of ketorolac state the concurrent administration of ketorolac with other NSAIDs or aspirin is contraindicated.(1,2)

Nsaids; Aspirin (>300 Mg); Salicylate/Ketorolac (Injectable)

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Possible additive or synergistic side effects.(1)

CLINICAL EFFECTS: Concurrent use of multiple doses of ketorolac with other non-steroidal anti-inflammatory agents (NSAIDs), salicylates or aspirin may result in an increase in NSAID-related side effects such as bleeding or renal impairment.(1-3)

PREDISPOSING FACTORS: Patients with pre-existing renal impairment may be at an increased risk of adverse effects from this interaction. The risk for bleeding episodes may be greater in patients with multiple disease-associated factors (e.g. thrombocytopenia, advanced liver disease). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g., anticoagulants, antiplatelets, corticosteroids, selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs). Risk of GI bleed may be increased in patients who are of older age, in poor health status, or who use alcohol or smoke. Risk may also be increased with longer duration of NSAID use and prior history of peptic ulcer disease and/or GI bleeding.

PATIENT MANAGEMENT: The manufacturer of ketorolac states that concurrent use of ketorolac with either other NSAIDs, salicylates or aspirin is contraindicated.(1) If concurrent therapy is deemed medically necessary, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory tests (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling.

DISCUSSION: Manufacturers of ketorolac state that concurrent use of ketorolac with either other NSAIDs, salicylates or aspirin is contraindicated.(1,2) If concurrent therapy is deemed medically necessary, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. Conduct periodic monitoring of renal function, especially in patients with renal impairment.

Selected Nephrotoxic Agents/Bacitracin

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Bacitracin may cause renal failure due to glomerular and tubular necrosis. Concurrent administration of other nephrotoxic agents may result in additive renal toxicity.(1-3)

CLINICAL EFFECTS: Concurrent use of bacitracin with other potentially nephrotoxic agents may result in renal toxicity.(1-3)

PREDISPOSING FACTORS: Dehydration and high-dose bacitracin may predispose to adverse renal effects.(1)

PATIENT MANAGEMENT: Health Canada states that bacitracin is contraindicated in patients with renal impairment, including those taking other nephrotoxic drugs.(1) The Canadian and US manufacturers of bacitracin state that concomitant use of bacitracin with other potentially nephrotoxic agents should be avoided.(2,3)

DISCUSSION: Renal impairment is a major toxicity of bacitracin. Cases of nephrotoxicity have been reported when bacitracin was used off-label.(1-3)

Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

Alum;Ca;Mag/Oral Phosphate Supplements; Urinary Ph Modifiers

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Medications containing significant amounts of aluminum, calcium, or magnesium may bind to the phosphate and prevent its absorption.(1)

CLINICAL EFFECTS: Concurrent use of medications containing significant amounts of aluminum, calcium, or magnesium may result in decreased effectiveness of phosphate supplements and urinary pH modifiers high in phosphate.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Patients receiving phosphate supplements or urinary pH modifiers high in phosphate should be instructed to avoid medications containing aluminum, calcium, or magnesium.(1) If concurrent use cannot be avoided, separate the administration of phosphate containing products by as much time as possible from medications containing aluminum, calcium, or magnesium. Some phosphate laxative products used as phosphate supplements may contain sufficient quantities of phosphate to interact as well.

DISCUSSION: The manufacturer of K-Phos states that products containing aluminum, calcium, or magnesium may bind to the phosphate and prevent its absorption. Therefore, patients receiving phosphate supplements and urinary pH modifiers high in phosphate should be instructed to avoid products containing aluminum, calcium, or magnesium.(1)

Aluminum & Magnesium Antacids;Polyvalent Cations/Raltegravir

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Aluminum and/or magnesium containing antacids may alter raltegravir absorption by altering gastric pH. Magnesium antacids and supplements containing polyvalent cations may bind to raltegravir in the GI tract, preventing its absorption.(1)

CLINICAL EFFECTS: Aluminum and/or magnesium containing antacids and supplements containing polyvalent cations may reduce levels and clinical effectiveness of raltegravir.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Concurrent use of any formulation of raltegravir and aluminum and/or magnesium antacids is not recommended. Instruct patients not to use aluminum and/or magnesium containing antacids. Calcium carbonate may be used in place of aluminum and/or magnesium containing antacids in patients receiving raltegravir twice daily. Calcium carbonate is not recommended for patients receiving once daily raltegravir (1,200 mg daily).(1,2) The US HIV treatment guidelines state that if coadministration of other medications that contain polyvalent cations (e.g., Mg, Al, Fe, Ca, Zn, sucralfate) is necessary, administer raltegravir at least 2 hours before or at least 6 hours after polyvalent cations. Monitor for virologic response.(2)

DISCUSSION: Simultaneous administration of aluminum and magnesium hydroxide (20 ml) with raltegravir (400 mg BID) decreased raltegravir maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) by 44%, 49%, and 63%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 2 hours before raltegravir (400 mg BID) decreased raltegravir Cmax, AUC, and Cmin by 51%, 51%, and 56%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 2 hours after raltegravir (400 mg BID) decreased raltegravir Cmax, AUC, and Cmin by 22%, 30%, and 57%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 4 hours before after raltegravir (400 mg BID) decreased raltegravir Cmax, AUC, and Cmin by 22%, 19%, and 60%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 4 hours after after raltegravir (400 mg BID) decreased raltegravir Cmax, AUC, and Cmin by 30%, 32%, and 62%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 6 hours before after raltegravir (400 mg BID) decreased raltegravir Cmax, AUC, and Cmin by 10%, 13%, and 50%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 6 hours after after raltegravir (400 mg BID) decreased raltegravir Cmax, AUC, and Cmin by 10%, 11%, and 49%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 12 hours after after raltegravir (1200 mg single dose) decreased raltegravir Cmax, AUC, and Cmin by 14%, 14%, and 58%, respectively.(1,3) Data from in vitro(3) and in vivo simulations(5) suggest that magnesium's effect on raltegravir may involve chelation as well as changes in pH.

Anticoagulants; Antiplatelets/Inotersen

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Inotersen causes reductions in platelet count that may result in sudden and unpredictable thrombocytopenia.(1)

CLINICAL EFFECTS: Concurrent use of inotersen with anticoagulants and/or antiplatelet agents may result in additive or synergistic effects, including fatal and non-fatal intracranial hemorrhage.(1)

PREDISPOSING FACTORS: The risk for bleeding episodes may also be greater in patients greater than 60 years or have a prior history of major bleeding events. Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Inotersen should be administered with caution in patients receiving anticoagulants and/or antiplatelet agents.(1) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. Monitor platelet count frequently. If platelet count is less than 50, stop inotersen treatment and consider discontinuation of any anticoagulant and/or antiplatelet agents. Monitor for signs and symptoms of thrombocytopenia; such as, unusual or prolonged bleeding (petechiae, easy bruising, hematoma, subconjunctival bleeding, gingival bleeding, epistaxis, hemoptysis, irregular or heavier than normal menstrual bleeding, hematemesis, hematuria, hematochezia, melena), neck stiffness, or atypical severe headache.

DISCUSSION: In a clinical study, platelet counts below 100 occurred in 25% of inotersen-treated patients, compared with 2% of patients on placebo. Platelet counts below 75 occurred in 14% of inotersen-treated patients, compared to no patients on placebo. In study 1 and its extension study, 39% of inotersen-treated patients with a baseline platelet count below 200 had a nadir platelet count below 75, compared to 6% of patients with baseline platelet counts 200 or higher. Three inotersen-treated patients (3%) had sudden severe thrombocytopenia (platelet count below 25). One patient experienced a fatal intracranial hemorrhage.(1) Inotersen is only available through a Tegsedi REMS program because of the risk of severe thrombocytopenia and the risk of glomerulonephritis.(1)

Anticoagulants; Antiplatelets; Thrombolytics/Caplacizumab

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Bleeding has been reported with the use of caplacizumab.(1)

CLINICAL EFFECTS: Concurrent use of caplacizumab with anticoagulants, antiplatelets, or thrombolytics may increase the risk of hemorrhage.(1)

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. hemophilia, coagulation factor deficiencies). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Avoid the use of caplacizumab with anticoagulants, antiplatelets, and thrombolytics. Interrupt caplacizumab therapy if clinically significant bleeding occurs. Patients may require von Willebrand factor concentrate to rapidly correct hemostasis. If caplacizumab is restarted, closely monitor for signs of bleeding.(1) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory tests (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug.

DISCUSSION: Bleeding has been reported with caplacizumab. In clinical studies, severe bleeding adverse reactions of epistaxis, gingival bleeding, upper gastrointestinal hemorrhage, and metrorrhagia were each reported in 1% of patients. Overall, bleeding events occurred in approximately 58% of patients on caplacizumab versus 43% of patients on placebo.(1) In post-marketing reports, cases of life-threatening and fatal bleeding were reported with caplacizumab.(1)

Aspirin(>100Mg);Salicylates/Slt Anticoagulants (Vit K Antag)

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Multiple processes are involved: 1) Salicylate doses greater than 3 gm daily decrease plasma prothrombin levels. 2) Salicylates may also displace anticoagulants from plasma protein binding sites. 3) Aspirin is an irreversible platelet inhibitor. Salicylates impair platelet function, resulting in prolonged bleeding time. 4) Salicylates may cause gastrointestinal(GI) bleeding due to irritation.

CLINICAL EFFECTS: The concurrent use of anticoagulants and salicylates leads to blockade of two distinct coagulation pathways and may increase the risk for bleeding.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Avoid concomitant administration of these drugs. When aspirin is required for cardioprotection, a low dose (less than 100 mg daily) is recommended to decrease the risk for aspirin-induced GI bleeding. The Australian manufacturer of fluindione states use is contraindicated with anti-inflammatory doses of acetylsalicylic acid (>= 1 g/dose and/or >= 3 g/day) and analgesic or antipyretic doses (>= 500 mg per dose and/or < 3 g per day) with a history of duodenal ulcer. Use is not recommend for analgesic or antipyretic doses (>= 500 mg per dose and/or <3 g per day) in the absence of a history of duodenal ulcer. If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling.

DISCUSSION: This interaction has been reported between aspirin and warfarin and between aspirin and dicumarol. Diflunisal, sodium salicylate, and topical methyl salicylate have been shown to interact with anticoagulants as well. Based on the proposed mechanisms, other salicylates would be expected to interact with anticoagulants as well. A self-controlled case study of 1,622 oral anticoagulant-precipitant drug pairs were reviewed and found 14% of drug pairs were associated with a statistically significant elevated risk of thromboembolism. Concurrent use of warfarin and diflunisal resulted in a ratio of rate ratios (RR) (95% CI) of 3.85 (1.34-11.03); warfarin and aspirin ratio of RR 2.13 (1.72-2.64); warfarin and dipyridamole ratio of RR 2.07 (1.65-2.6); and warfarin and clopidogrel ratio of RR 1.69 (1.56-1.84). A large systematic review was performed on 72 warfarin drug-drug interactions studies that reported on bleeding, thromboembolic events, or death. Most studies were retrospective cohorts. A meta-analysis of 38 of those studies found a higher rate of clinically significant bleeding in patients on warfarin and antiplatelets (OR=1.74; 95% CI 1.56-1.94). Increased bleeding risk was also seen in subgroup analyses with aspirin (OR=1.50; 95% CI 1.29-1.74), clopidogrel (OR=3.55; 95% CI 2.78-4.54), and aspirin plus clopidogrel or ticlopidine (OR=2.07, 95% CI 1.33-3.21).(17)

Nsaids; Aspirin (> 100 Mg); Salicylates/Mifamurtide

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: High-dose NSAIDs or salicylates may block the macrophage activating effect of mifamurtide.(1)

CLINICAL EFFECTS: Concurrent use of high-dose NSAIDs or salicylates may decrease the effectiveness of mifamurtide.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The UK manufacturer of mifamurtide states that concurrent use with high-dose NSAIDs or salicylates is contraindicated.(1)

DISCUSSION: In vitro studies have shown that high-dose NSAIDs or salicylates can block the macrophage activating effect of mifamurtide.(1)

Nsaids; Salicylates/Dabigatran

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Dabigatran is a direct thrombin inhibitor and when taken with agents that effect platelet aggregation and/or other clotting factors increased bleeding episodes can occur.(1,2)

CLINICAL EFFECTS: Concurrent use of dabigatran with NSAIDs or salicylates may result in additive or synergistic effects resulting in unwanted bleeding episodes.(1)

PREDISPOSING FACTORS: Factors associated with an increased risk for bleeding include renal impairment, concomitant use of P-glycoprotein inhibitors, patient older than 74 years, coexisting conditions (e.g. recent trauma, thrombocytopenia, advanced liver disease), use of drugs associated with bleeding risk (e.g. other anticoagulants, antiplatelets, corticosteroids, selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs)), and patient weight less than 50 kg. (1-3) Risk of GI bleed may be increased in patients who are of older age, in poor health status, who use alcohol or smoke, with longer duration of NSAID use, and with prior history of peptic ulcer disease and/or GI bleeding.

PATIENT MANAGEMENT: Monitor patients receiving concurrent therapy for signs of blood loss and promptly evaluate patients with any symptoms. Discontinue dabigatran in patients with active pathological bleeding.(1) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling.

DISCUSSION: Dabigatran is a direct thrombin inhibitor and when taken with agents that effect platelet aggregation and/or other clotting factors increased bleeding episodes can occur.(1,2) A post hoc analysis of nonselective NSAIDs in the RE-LY study (compared dabigatran 150 and 110 mg twice daily with warfarin in atrial fibrillation) assessed clinical outcomes by comparing nonselective NSAID use (at least once during trial) with no NSAID use in 2279 patients. The use of NSAIDs was associated an increased risk of major bleeding (hazard ratio (HR) 1.68), gastrointestinal major bleeding (HR 1.81), stroke or systemic embolism (HR 1.50), and hospitalization (HR 1.64).(22)

Nsaids; Salicylates/Selected Immunosuppressants

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Cyclosporine increases the production of prostaglandin E2 and I2. Prostaglandin E2 has been shown to prevent cyclosporine -induced renal toxicity in animals. NSAIDS and salicylates may increase cyclosporine-induced renal toxicity by blocking the formation of prostaglandins. Concurrent use of everolimus, sirolimus or tacrolimus with NSAIDs or salicylates may result in additive nephrotoxicity.

CLINICAL EFFECTS: Concurrent administration of cyclosporine, everolimus, sirolimus, or tacrolimus and a NSAID or salicylate may result in a decrease in renal function, with or without an alteration in immunosuppressant levels.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: If possible, avoid the concurrent use of NSAIDs or salicylates in patients maintained on cyclosporine, everolimus, sirolimus, or tacrolimus. If concurrent therapy is warranted, patients should be monitored for a decrease in renal function. The NSAID or salicylate may need to be discontinued.

DISCUSSION: A decrease in renal function has been reported with concurrent cyclosporine and diclofenac, sulindac, mefenamic acid, ketoprofen, piroxicam, and naproxen. Decreasing the cyclosporine dose without discontinuing the NSAID does not appear to improve renal function. The use of agents which decrease renal function concurrently with everolimus, sirolimus or tacrolimus should be approached with caution. An observational study of 63 inpatient encounters for 57 transplant patients evaluated concurrent use between calcineurin inhibitor (CNI) therapy and NSAID use. Patients were matched to 126 transplant patients on CNI therapy without NSAID use. Patients who received at least one dose of NSAID had a 12.2% rate of treatment emergent acute kidney injury (AKI). The relative risk ratio for AKI in patient exposed to NSAID therapy was 2.20 (95% CI 0.74-6.54). An increase in 48 hour post NSAID exposure serum creatinine above baseline was documented in 65.9% of patients compared to 46% in the non NSAID group (p=0.016). Multivariate analysis revealed changes in serum creatinine at 48 hours after admission were independently associated with age (p=0.008) and NSAID use (p=0.026).(12)

Nsaids; Salicylates/Selected Platelet Aggregation Inhibitors

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Abciximab, cangrelor, cilostazol, clopidogrel, dipyridamole, eptifibatide, prasugrel, ticagrelor, vorapaxar and NSAIDs or salicylates inhibit platelet aggregation.

CLINICAL EFFECTS: Concurrent use of platelet aggregation inhibitors and NSAIDs or salicylates may increase the risk of bleeding.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with multiple disease-associated factors (e.g. thrombocytopenia, advanced liver disease). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g., anticoagulants, other antiplatelets, corticosteroids, selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs). Risk of GI bleed may be increased in patients who are of older age, in poor health status, or who use alcohol or smoke. Risk may also be increased with longer duration of NSAID use and prior history of peptic ulcer disease and/or GI bleeding. Risk increases as the number of risk factors increases.

PATIENT MANAGEMENT: Use caution when administering platelet aggregation inhibitors with NSAIDs or salicylates.(1-5) It would be prudent to monitor patients more closely during concurrent therapy and to use the lowest NSAID or salicylate dose possible. If concurrent therapy is warranted, monitor patients for signs of blood loss, including decreased hemoglobin and/or hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The 2010 ACCF/ACG/AHA Consensus guidelines recommend the use of proton pump inhibitors (PPIs) in patients with multiple risk factors for GI bleeding who require antiplatelet therapy. However, esomeprazole and omeprazole should be avoided with clopidogrel as they are expected to reduce the effectiveness of clopidogrel. Use of other PPIs should be approached with caution, as they may reduce the effectiveness of clopidogrel.

DISCUSSION: Because of the increased risk of bleeding, caution is warranted when using this combination. In a nationwide cohort study, patients were evaluated for thromboembolic cardiovascular and clinically relevant bleeding events with concurrent antithrombotic and ongoing NSAID treatment. A total of 108,232 patients were followed for a mean of 2.3 +/- 1.8 years after diagnosis of myocardial infarction. Concomitant NSAID treatment significantly increased the risk for cardiovascular events (hazard ratio (HR) 6.96; 95% CI 6.24 - 6.77; p<0.001) and bleeding events (HR 4.08; 95% CI 3.51 - 4.73; p<0.001) compared to no NSAID treatment. NSAIDs were further evaluated and revealed the use of celecoxib (HR: 4.65; 95% CI: 3.17 to 6.82; p < 0.001, and 3.44; 95% CI: 2.20 to 5.39; p < 0.001, respectively) and meloxicam (HR: 3.03; 95% CI: 1.68 to 5.47; p < 0.001, and 2.80; 95% CI: 1.40 to 5.60; p < 0.001, respectively) had the lowest risk for cardiovascular and bleeding events, receptively.

Nsaids; Salicylates/Sodium Phosphate Bowel Cleanser

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Bowel cleansing with sodium phosphate causes dehydration, decreased intravascular volume and hyperphosphatemia, which increases phosphate levels in the renal tubules. Abnormally high levels of calcium and phosphate in the renal tubules may precipitate out, resulting in renal injury.(1)

CLINICAL EFFECTS: Use of sodium phosphate for bowel cleansing in patients maintained on nonsteroidal anti-inflammatory drugs (NSAIDs) may increase the risk of acute phosphate nephropathy, which is an acute kidney injury associated with deposits of calcium phosphate crystal in the renal tubules that may result in permanent renal function impairment. Acute phosphate nephropathy presents as acute kidney injury with minimal proteinuria and a bland urine sediment.(2) Use of oral sodium phosphate products at laxative doses has not been associated with acute kidney injury.(3)

PREDISPOSING FACTORS: Patients who may be at an increased risk of acute phosphate nephropathy include those who are over age 55; are hypovolemic or have decreased intravascular volume; have baseline kidney disease, bowel obstruction, or active colitis; and who are using medications that affect renal perfusion or function (such as diuretics, ACE inhibitors, angiotension receptor blockers [ARBs]), and NSAIDs.(2)

PATIENT MANAGEMENT: If possible, use an alternative agent for bowel cleansing.(1) Use sodium phosphate products with caution in patients taking medications that affect kidney function or perfusion, such as ACE inhibitors or ARBs. Obtain baseline and post-procedure labs (electrolytes, calcium, phosphate, BUN, creatinine, and [in smaller, frail individuals] glomerular filtration rate). Instruct patients to drink sufficient quantities of clear fluids before, during, and after bowel cleansing and to avoid other laxatives that contain sodium phosphate. Consider hospitalization and intravenous hydration during bowel cleansing to support frail patients who may be unable to drink an appropriate volume of fluid or who may be without assistance at home.(2) Use of an electrolyte solution for rehydration may decrease the risk of acute phosphate nephropathy.(4,5)

DISCUSSION: Since May 2006, the FDA has received 20 reports of acute phosphate nephropathy associated with the use of Osmo Prep. Concomitant medications included ACE inhibitors or ARBs (11), diuretics (6), and NSAIDs (4).(2) In a retrospective review of colonoscopy patients, simultaneous use of ACE inhibitors or ARBs significantly increased the risk of acute kidney injury from oral sodium phosphate. Diuretic use was also a risk factor.(6) In a case series study of 21 cases of acute phosphate nephropathy in patients who had used oral sodium phosphate, 14 patients received an ACE inhibitor or ARB, 4 used a diuretic, and 3 used an NSAID.(7) Cases have also been reported with rectal products.(8)

Nsaids;Salicylates/Apixaban;Betrixaban;Edoxaban;Rivaroxaban

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Concurrent use of apixaban(1-4), betrixaban(7), edoxaban(5), or rivaroxaban(6) and nonsteroidal antiinflammatory agents (NSAIDs) or salicylates may result in additive increased risk of bleeding.

CLINICAL EFFECTS: Concurrent use of apixaban(1), betrixaban(7), edoxaban(5), or rivaroxaban(2) with NSAIDs or salicylates may result in unwanted bleeding episodes.

PREDISPOSING FACTORS: Bleeding risk may be increased in patients with renal impairment and in patients older than 75 years. The risk for bleeding episodes may be greater in patients with multiple disease-associated factors (e.g. thrombocytopenia, advanced liver disease). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g., other anticoagulants, antiplatelets, corticosteroids, selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs). Risk of GI bleed may be increased in patients who are of older age, in poor health status, or who use alcohol or smoke. Risk may also be increased with longer duration of NSAID use and prior history of peptic ulcer disease and/or GI bleeding.

PATIENT MANAGEMENT: Approach concurrent therapy with apixaban(1-4), betrixaban(7), edoxaban(5), or rivaroxaban(6) with caution. Monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling.

DISCUSSION: In a study, naproxen (500 mg) increased apixaban (10 mg) area-under-curve (AUC) and maximum concentration (Cmax) by 1.5-fold an 1.6-fold, respectively, with corresponding increases in clotting tests. There were no changes in the effect of naproxen on arachidonic acid-induced platelet aggregation, no clinically relevant changes in bleeding times, or naproxen pharmacokinetics.(1) In a single dose study, there were no pharmacokinetic or pharmacodynamic interactions between rivaroxaban and naproxen.(6) Although effects seen in the above studies were limited, NSAIDs are known to increase bleeding and may further increase the risk of bleeding with these agents.(1-6) In edoxaban clinical studies, concomitant use of low-dose aspirin (less than or equal to 100 mg/day) or thienopyridines, and NSAIDs was permitted and resulted in increased rates of clinically relevant bleeding.(5) In a study of 34 healthy subjects administered edoxaban 60 mg daily and naproxen 500 mg daily, bleeding time increased by 2.08-fold from baseline on the combination, compared to a 1.23-fold increase with naproxen alone and 1.7-fold increase on edoxaban alone.(8) A self-controlled case study of 1,622 oral anticoagulant-precipitant drug pairs were reviewed and found 14% of drug pairs were associated with a statistically significant elevated risk of thromboembolism. Concurrent use of apixaban and ibuprofen resulted in a ratio of rate ratios (RR) (95% CI) of 5.16 (3.0-8.85); apixaban and celecoxib ratio of RR 1.8 (1.06-3.06); rivaroxaban and etodolac ratio of RR 2.47 (1.18-4.22); rivaroxaban and naproxen ratio of RR 1.89 (1.12-1.43); and rivaroxaban and ibuprofen ratio of RR 1.68 (1.29-4.44).(9)

Salicylates/Influenza Virus Vaccine Live

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Use of salicylates during influenza infection has been associated with Reye's Syndrome.(1,2)

CLINICAL EFFECTS: Use of the live influenza virus vaccine in children and adolescents (patients age 2-17 years) receiving salicylate therapy may increase the risk of Reye's Syndrome.(1,2) Symptoms of Reye's syndrome include drowsiness, confusion, seizures, coma. In severe cases, Reye's syndrome can result in death.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The use of live influenza virus vaccine in children and adolescents (patients age 2-17 years) receiving salicylate therapy is contraindicated.(1,2) Use of salicylates should be avoided for 4 weeks after administration of live influenza vaccine.(1)

DISCUSSION: Because the use of salicylates during influenza infection has been associated with Reye's Syndrome, the use of live influenza virus vaccine in children and adolescents (patients age 2-17 years) receiving salicylate therapy is contraindicated.(1,2)

Salicylates/Varicella Virus Vaccine Live

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Use of salicylates during natural varicella infection has been associated with Reye's Syndrome.(1-4)

CLINICAL EFFECTS: Use of the live varicella virus vaccine in patients receiving salicylate therapy or use of salicylates within 6 weeks after vaccination with the live varicella virus vaccine may increase the risk of Reye's Syndrome.(1-4) Symptoms of Reye's syndrome include drowsiness, confusion, seizures, coma. In severe cases, Reye's syndrome can result in death.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The Canadian, UK, and US manufacturers of live varicella virus vaccine indicated for the prevention of chicken pox state that vaccine recipients should avoid the use of salicylates for 6 weeks after vaccination.(1-4) There is no such restriction in the labeling for live varicella virus vaccine indicated for the prevention of shingles, which is only indicated for patients age 60 and older.(5)

DISCUSSION: Because the use of salicylates during natural varicella infection has been associated with Reye's Syndrome, the use of salicylates for 6 weeks following vaccination with live varicella virus vaccine should be avoided.(1-4)

Select Salicylates/Methotrexate (Low Strength Inj, Oral)

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Salicylates may inhibit the renal tubular excretion of methotrexate.

CLINICAL EFFECTS: The concurrent use of methotrexate and salicylates may result in an increase in the therapeutic and toxic effects of methotrexate, leading to increased risk of severe neurotoxicity, stomatitis, and myelosuppression, including neutropenia.

PREDISPOSING FACTORS: Risk factors for methotrexate toxicity include: - High-dose oncology regimens - Anti-inflammatory doses of aspirin/salicylates - impaired renal function, ascites, or pleural effusions

PATIENT MANAGEMENT: US manufacturer prescribing information for methotrexate states nonsteroidal anti-inflammatory drugs, including salicylates should not be administered prior to or concomitantly with high doses of methotrexate. If concurrent therapy is warranted, methotrexate plasma levels should be monitored and patients should be observed for methotrexate toxicity. The dosage of methotrexate may need to be adjusted. Use caution when administering salicylates and low dose methotrexate. Salicylate doses > or = 2 grams per day have been associated with hepatic impairment or impaired renal elimination of methotrexate. It would be prudent to avoid high-dose aspirin, especially in patients with renal impairment or near the time of methotrexate dosage (in patients receiving weekly therapy). The Australian prescribing information for aspirin DL-lysine states coadministration with methotrexate at doses of 15 mg/week or greater is contraindicated.

DISCUSSION: Several studies and case reports have reported increased and prolonged methotrexate levels in patients receiving concurrent aspirin. One study noted an effect with average weekly doses of methotrexate of 16.6 mg, but not weekly doses of 7.5 mg. Decreased renal function has also been reported with the combination. Single ingredient aspirin or buffered aspirin products with strengths < or = to 325 mg or formulations which are associated with once daily use for cardiovascular protection are not linked to this interaction. Other lower-strength aspirin formulations (e.g. headache, cough & cold, opioid combinations) which could be consumed multiple times a day remain linked to this interaction.

Selected Nephrotoxic Agents/Colistimethate

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Colistimethate can cause nephrotoxicity.(1,2) Concurrent administration of other nephrotoxic agents may result in an increased risk of nephrotoxicity.(1) It is suspected that cephalothin interferes with the excretion of colistimethate resulting in enhanced nephrotoxicity.(2,3)

CLINICAL EFFECTS: Concurrent use of colistimethate with other nephrotoxic agents may result in additive nephrotoxic effects.

PREDISPOSING FACTORS: Factors predisposing to nephrotoxicity include higher cumulative doses of colistimethate, longer treatment duration, hypovolemia, and critical illness.

PATIENT MANAGEMENT: Concurrent use of potentially nephrotoxic agents with colistimethate should be avoided.(1,2) If concurrent use is necessary, it should be undertaken with great caution.(1)

DISCUSSION: In a case control study of 42 patients on intravenous colistimethate sodium, NSAIDs were identified as an independent risk factor for nephrotoxicity (OR 40.105, p=0.044).(4) In 4 case reports, patients developed elevated serum creatinine and blood urea nitrogen following concurrent colistimethate and cephalothin (3 patients) or when colistimethate followed cephalothin therapy (1 patient).(3) A literature review found that individual nephrotoxic agents, including aminoglycosides, vancomycin, amphotericin, IV contrast, diuretics, ACE inhibitors, ARBs, NSAIDs, and calcineurin inhibitors, were not consistently associated with additive nephrotoxicity when used with colistimethate. However, when multiple agents (at least 2 additional potential nephrotoxins) were used concurrently, there was a significant correlation to colistimethate nephrotoxicity.(5)

Selected Nsaids; Aspirin (>325 Mg)/Pemetrexed

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: NSAIDs may decrease the clearance of pemetrexed.(1) This decreased clearance may be the result of chronic renal toxicity from NSAIDs or NSAIDs may compete with pemetrexed for tubular secretion.(2)

CLINICAL EFFECTS: Concurrent use of pemetrexed and NSAIDs may result in elevated levels of and toxicity from pemetrexed, including myelosuppression, neutropenia, renal toxicity, and gastrointestinal toxicity.(1)

PREDISPOSING FACTORS: This interaction is expected to be more severe in patients with mild to moderate renal insufficiency (creatinine clearance (CrCl) of 45 ml/min to 79 ml/min) and/or patients taking long acting NSAIDs. (1)

PATIENT MANAGEMENT: In patients with normal renal function (CrCl equal to or greater than 80 ml/min), ibuprofen (400 mg 4 times daily) can be administered with pemetrexed. Aspirin in low to moderate doses (325 mg every 6 hours) does not affect the pharmacokinetics of pemetrexed.(1) In patients with mild to moderate renal insufficiency (CrCl from 45 ml/min to 79 ml/min), NSAIDs with short half-lives should be avoided for 2 days before, the day of, and 2 days after pemetrexed administration. Ibuprofen should be administered with caution in these patients.(1) NSAIDs and salicylates with long half-lives should be avoided for at least 5 days before, the day of, and 2 days following pemetrexed administration in all patients.(1,2) If NSAIDs are required, patients should be monitored for pemetrexed toxicity, especially myelosuppression, renal toxicity, and gastrointestinal toxicity.(1)

DISCUSSION: In patients with normal renal function, ibuprofen (400 mg 4 times daily) decreased the clearance of pemetrexed by 20% and increased its area-under-curve (AUC) by 20%.(1) In a Phase I clinical trial, two patients receiving high dose pemetrexed therapy experienced severe toxicity, both were receiving a NSAID. Following these reports, all patients were required to stop aspirin or other NSAIDs 2 days before and not resume these agents until 2 days after pemetrexed.(2) In two randomized, controlled cross-over trials, 27 cancer patients with a creatinine clearance (CrCl) less than or equal to 60 ml/min received pemetrexed (500 mg/m2) infusion on Day 1 of a 21-day cycle and either aspirin 325 mg or ibuprofen 400 mg orally every 6 hours starting 2 days before pemetrexed administration. Coadministration of aspirin did not affect pemetrexed pharmacokinetics. Ibuprofen decreased the clearance of pemetrexed by 16%, increased its maximum concentration (Cmax) by 15%, and increased the AUC by 20%.(3) Aspirin products linked to this monograph are single ingredient aspirin products with greater than 325 mg strength, and aspirin combination products (e.g. opioid-aspirin or cough/cold/allergy products) with a reasonable likelihood of a total daily aspirin dose > or = 1,300 mg per day.

Selected Salicylates/Methotrexate (Oncology-Injection)

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Salicylates may inhibit the renal tubular excretion of methotrexate.

CLINICAL EFFECTS: The concurrent use of methotrexate and salicylates may result in an increase in the therapeutic and toxic effects of methotrexate, leading to increased risk of severe neurotoxicity, stomatitis, and myelosuppression, including neutropenia.

PREDISPOSING FACTORS: Risk factors for methotrexate toxicity include: - High-dose oncology regimens - Anti-inflammatory doses of aspirin/salicylates - Impaired renal function, ascites, or pleural effusions

PATIENT MANAGEMENT: US manufacturer prescribing information for methotrexate states nonsteroidal anti-inflammatory drugs should not be administered prior to or concomitantly with high doses of methotrexate. If concurrent therapy is warranted, methotrexate plasma levels should be monitored and patients should be observed for methotrexate toxicity. The dosage of methotrexate may need to be adjusted. Use caution when administering higher doses of salicylates with lower doses of methotrexate. Salicylate doses > or = 2 grams per day have been associated with hepatic impairment or impaired renal elimination of methotrexate. It would be prudent to avoid high-dose aspirin, especially in patients with renal impairment or near the time of methotrexate dosage (in patients receiving weekly therapy). The Australian prescribing information for aspirin DL-lysine states coadministration with methotrexate at doses of 15 mg/week or greater is contraindicated.

DISCUSSION: Several studies and case reports have reported increased and prolonged methotrexate levels in patients receiving concurrent aspirin. One study noted an effect with average weekly doses of methotrexate of 16.6 mg, but not weekly doses of 7.5 mg. Decreased renal function has also been reported with the combination. Single ingredient aspirin or buffered aspirin products with strengths < or = to 325 mg or formulations which are associated with once daily use for cardiovascular protection are not linked to this interaction. Other lower-strength aspirin formulations (e.g. headache, cough & cold, opioid combinations) which could be consumed multiple times a day remain linked to this interaction.

Moderate Interaction: Assess the risk to the patient and take action as needed.

Aluminum, Iron, Zinc/Deferiprone

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Deferiprone chelates polyvalent cations such as aluminum, iron, and zinc.(1)

CLINICAL EFFECTS: Deferiprone chelation with oral aluminum, iron or zinc containing products in the gastrointestinal tract may decrease the amount of free deferiprone available for systemic iron chelation. Zinc supplements prescribed to counteract deferiprone-induced zinc deficiency may not be effective if taken near time of deferiprone administration.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The US manufacturer recommends at least a four hour interval between deferiprone dose and administration of aluminum, iron or zinc containing medications or supplements.(1) Avoid use of iron-containing vitamins or nutritional supplements in patients who require chelation therapy for iron overload.

DISCUSSION: The US manufacturer has not studied this interaction. The recommendation to separate deferiprone and polyvalent cation doses by at least four hours is based upon the deferiprone mechanism of action.(1)

Aluminum-Magnesium Hydroxide; Oral Calcium/Phenytoin

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Aluminum hydroxide; magnesium hydroxide, and oral calcium may bind to phenytoin, preventing its absorption.(1-4)

CLINICAL EFFECTS: Simultaneous ingestion of aluminum-magnesium hydroxide and/or calcium-containing products may result in decreased levels and effectiveness of phenytoin.(1-4)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The US manufacturer of phenytoin recommends that administration times of phenytoin and antacids being staggered.(1)

DISCUSSION: In a study in 8 healthy subjects, simultaneous administration of phenytoin (600 mg) with calcium carbonate significantly decreased the area-under-curve (AUC) of phenytoin.(2) In a study in 8 healthy subjects, simultaneous administration of aluminum-magnesium hydroxide or calcium carbonate significantly decreased the AUC of phenytoin.(3) In a study in 6 patients with epilepsy, concurrent administration of an aluminum-magnesium hydroxide antacid resulted in a small but statistically significant decrease in phenytoin AUC.(4)

Aluminum; Magnesium Compounds/Selected Cephalosporins

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Aluminum and magnesium containing antacids may form chelation complexes with some cephalosporins, preventing their absorption.(1,2)

CLINICAL EFFECTS: Simultaneous administration of an aluminum and/or magnesium containing antacid with some cephalosporins may result in decreased levels and effectiveness of the cephalosporin.(1,2)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The manufacturer of cefdinir recommends that cefdinir be taken at least 2 hours before or after an aluminum and/or magnesium containing antacid.(1) It would be prudent to separate the administration of cefaclor by at least this amount of time as well.(2)

DISCUSSION: Simultaneous administration of cefdinir (300 mg) with Maalox TC (30 ml) decreased cefdinir area-under-curve (AUC) and maximum concentration (Cmax) by 40%.(1) In a study in 15 healthy subjects, simultaneous administration of cefaclor advanced formulation (500 mg) with Maalox TC decreased the extent of cefaclor absorption.(2)

Aluminum; Magnesium-Containing Compounds/Gabapentin

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Aluminum or magnesium containing products may reduce the bioavailability of gabapentin.(1)

CLINICAL EFFECTS: Simultaneous administration of aluminum or magnesium containing products and gabapentin may result in decreased absorption of gabapentin by 20% and reduce its clinical effectiveness.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: If the use of both medications is unavoidable, it is recommended that gabapentin be taken at least 2 hours following the administration of aluminum or magnesium containing products.(1)

DISCUSSION: In 16 subjects, Maalox reduced the bioavailability of gabapentin by about 20%. The reduction was only 5% when gabapentin was administered 2 hours after the Maalox dose. It is for this reason that the manufacturer of gabapentin recommends that it be taken at least 2 hours after the administration of aluminum or magnesium containing products.(1)

Antacids And Selected Minerals/Oral Iron Supplements

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Some antacids may bind to iron, preventing its absorption. Alterations in gastric pH by antacids may also play a role. Iron may bind to other minerals such as calcium, manganese, tin, and zinc in the GI tract.

CLINICAL EFFECTS: Simultaneous administration of an antacid or minerals may decrease the absorption of orally administered iron.

PREDISPOSING FACTORS: The interaction with some combinations may be affected by the presence or absence of food.

PATIENT MANAGEMENT: Iron supplements should not be taken within 1 hour before or 2 hours after antacids, calcium, manganese, or zinc.(1) Some vitamin preparations may contain sufficient quantities of calcium and/or magnesium salts with antacid properties to interact as well.

DISCUSSION: Magnesium hydroxide has been shown to inhibit the absorption of elemental iron,(2) although other studies have shown conflicting results.(3,4) Sodium bicarbonate has been shown to decrease the absorption of iron by 50%.(3) In a study in 61 healthy subjects, calcium citrate, calcium carbonate, and calcium phosphate inhibited iron absorption when taken with food. However, in the fasted state, calcium carbonate had no effect on iron absorption. In the fasted state, calcium citrate and calcium phosphate decreased iron absorption by 49% and 62%, respectively,(6) In a study in 23 healthy subjects, calcium acetate and calcium carbonate decreased the area-under-curve (AUC) of elemental iron (65 mg) by 27% and 19%, respectively.(7) In a study, manganese decreased iron absorption. A ratio of 5:1 of zinc:iron decreased iron absorption by 56%.(8) In a study, inorganic iron decreased zinc absorption.(9) In another study, ferrous sulfate decreased the absorption of zinc sulfate in a concentration dependent manner; however, heme chloride had no effect on zinc sulfate.(10) In a study in premature infants, administration of liquid zinc and iron supplements between feedings decreased iron uptake; however, no effect was seen when the supplements were mixed with feedings.(11) One or more of the drug pairs linked to this monograph have been included in a list of interactions that could be considered for classification as "non-interruptive" in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.

Anticoagulants; Antiplatelets/Fruquintinib; Surufatinib

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Bleeding has been reported with the use of fruquintinib and surufatinib.(1,2)

CLINICAL EFFECTS: Concurrent use of fruquintinib or surufatinib with either anticoagulants or antiplatelets may increase the risk of hemorrhage.(1,2)

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Patients receiving concurrent therapy with fruquintinib and anticoagulants and/or antiplatelets should be closely monitored for changes in platelet count or in International Normalized Ratio (INR). If a serious bleeding event occurs, the manufacturer recommends permanent discontinuation of fruquintinib.(1) Patients receiving concurrent therapy with surufatinib and anticoagulants and/or antiplatelets should be closely monitored for changes in platelet count or in INR.If a serious bleeding event occurs, the manufacturer recommends permanent discontinuation of surufatinib.(2) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory tests (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug.

DISCUSSION: Bleeding has been reported with fruquintinib in three randomized, double-blinded, placebo-controlled clinical trials. The incidence of grade 1 and grade 2 bleeding events was 28.2%, including gastrointestinal bleeding (10.9%), hematuria (10.6%), and epistaxis (7.5%). The incidence of grade 3 or higher bleeding events was 2.1% and included gastrointestinal bleeding (1.6%) and hemoptysis (0.5%).(1) Bleeding has been reported with surufatinib in clinical trials. Grade 1 and 2 bleeding events included gastrointestinal bleeding, blood in the urine, and gum bleeding. The incidence of grade 3 or greater bleeding events was 4.5%, including gastrointestinal hemorrhage (1.9%), and cerebral hemorrhage (1.1%). Fatalities due to bleeding were reported in 0.3% of patients. The incidence of permanent discontinuation due to bleeding was 2.6% and the incidence of suspension of surufatinib due to bleeding was 3.8%.(2)

Anticoagulants; Antiplatelets/Mifepristone (Cushing)

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Mifepristone is an antagonist at the progesterone receptor which can result in endometrium thickening, cystic dilatation of endometrial glands, or excessive vaginal bleeding. Concurrent use with anticoagulants or antiplatelets may further increase risk.

CLINICAL EFFECTS: The concurrent use of mifepristone with anticoagulants or antiplatelets may result in endometrium thickening, cystic dilatation of endometrial glands, or excessive vaginal bleeding.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: The manufacturer of mifepristone states that mifepristone should be used with caution in patients receiving concurrent anticoagulant or antiplatelet therapy.(1) If concurrent therapy is deemed medically necessary, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. Women experiencing vaginal bleeding during concurrent use should be referred to a gynecologist for further evaluation.

DISCUSSION: The manufacturer of mifepristone states that mifepristone should be used with caution in patients receiving concurrent anticoagulant or antiplatelet therapy.(1)

Anticoagulants; Antiplatelets/Obinutuzumab

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Severe and life-threatening thrombocytopenia has been reported during obinutuzumab therapy.(1) Anticoagulants and antiplatelets may have an additive risk of bleeding.

CLINICAL EFFECTS: Concurrent use of obinutuzumab with anticoagulants or antiplatelet agents may result in additive or synergistic effects, including fatal and non-fatal hemorrhage.(1)

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Monitor all patients frequently for thrombocytopenia and signs of bleeding. Consider withholding concomitant anticoagulants and antiplatelets, especially during the first cycle of obinutuzumab.(1) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling.

DISCUSSION: Obinutuzumab with chemotherapy has been reported to cause severe and life-threatening thrombocytopenia. Fatal hemorrhagic events have occurred in patients with NHL and CLL during obinutuzumab therapy, including during Cycle 1.(1)

Anticoagulants; Antiplatelets/Plasminogen

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Bleeding has been reported with the use of plasminogen.(1)

CLINICAL EFFECTS: Concurrent use of plasminogen with either anticoagulants or antiplatelets may increase the risk of active bleeding during plasminogen therapy, including bleeding from mucosal disease-related lesions that may manifest as gastrointestinal (GI) bleeding, hemoptysis, epistaxis, vaginal bleeding, or hematuria.(1)

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Patients receiving concurrent therapy with plasminogen and anticoagulants and/or antiplatelets should be closely monitored during plasminogen therapy for active bleeding from mucosal disease-related lesions, including GI bleeding, hemoptysis, epistaxis, vaginal bleeding, or hematuria.(1) Prior to initiation of treatment with plasminogen, confirm healing of lesions or wounds suspected as a source of a recent bleeding event. Monitor patients during and for 4 hours after infusion when administering plasminogen with concurrent anticoagulants, antiplatelet drugs, or other agents which may interfere with normal coagulation.(1) If patient experiences uncontrolled bleeding (defined as any gastrointestinal bleeding or bleeding from any other site that persists longer than 30 minutes), seek emergency care and discontinue plasminogen immediately.(1) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory tests (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug.

DISCUSSION: Plasminogen has not been studied in patients at an increased risk of bleeding. Bleeding has been reported with plasminogen in a two single-arm, open-label clinical trials as well as in compassionate use programs. The incidence of hemorrhage in patients with Plasminogen Deficiency Type 1 was 16% (3/19 patients).(1) One of the bleeding events occurred two days after receiving the second dose of plasminogen in a patient with a recent history of GI bleeding due to gastric ulcers. The patient received plasminogen through a compassionate use program and the dose was 6.6 mg/kg body weight every 2 days. Endoscopy showed multiple ulcers with one actively bleeding ulcer near the pylorus.(1)

Anticoagulants; Antiplatelets/Tisotumab

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Bleeding, including hemorrhage, has been reported with the use of tisotumab.(1)

CLINICAL EFFECTS: Concurrent use of tisotumab with either anticoagulants, antiplatelets, or NSAIDs may increase the risk of hemorrhage.(1)

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Patients receiving concurrent therapy with tisotumab and anticoagulants, antiplatelets, and/or NSAIDs should be closely monitored for signs and symptoms of bleeding and changes in platelet count or International Normalized Ratio (INR). For patients experiencing pulmonary or central nervous system (CNS) hemorrhage, permanently discontinue tisotumab. For grade 2 or greater hemorrhage in any other location, withhold until bleeding has resolved, blood hemoglobin is stable, there is no bleeding diathesis that could increase the risk of continuing therapy, and there is no anatomical or pathologic condition that can increase the risk of hemorrhage. After resolution, either resume treatment or permanently discontinue tisotumab.(1) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory tests (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug.

DISCUSSION: Hemorrhage occurred in 62% of patients with cervical cancer treated with tisotumab across clinical trials. The most common all grade hemorrhage adverse reactions were epistaxis (44%), hematuria (10%), and vaginal hemorrhage (10%). Grade 3 hemorrhage occurred in 5% of patients.(1)

Aspirin (> 100 Mg); Salicylates/Acetazolamide; Methazolamide

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Acetazolamide and methazolamide may reduce blood pH, causing a shift of salicylates from plasma into tissues (eg, central nervous system). Alternatively, toxicity may be due to salicylate-induced displacement of the carbonic anhydrase inhibitor from its protein binding sites and inhibition of renal tubular secretion.

CLINICAL EFFECTS: An increase in the pharmacologic effects of salicylates with possible toxicity may occur.

PREDISPOSING FACTORS: High doses of salicylates, low body weight.

PATIENT MANAGEMENT: Avoid the combination if possible. If it is necessary to administer these drugs concurrently, monitor salicylate levels and monitor the patient for symptoms of toxicity. Adjust the dose as needed.

DISCUSSION: Two young patients with unimpaired renal and hepatic function were found to have developed metabolic acidosis after treatment for glaucoma and joint pain with a combination of salicylates and carbonic anhydrase inhibitors in normal doses.(1) A 67-year old woman and a 75-year old woman taking carbonic anhydrase inhibitors for therapy of glaucoma and high doses of aspirin for arthritis developed severe acid-base imbalance and salicylate intoxication.(2) Neither patient exhibited ill effects when taking high aspirin doses without a carbonic anhydrase inhibitor. Carbonic anhydrase inhibitor-induced acidemia increases the risk of developing salicylate intoxication in patients receiving high aspirin doses. Two elderly patients, who were chronically receiving aspirin developed lethargy, incontinence, and confusion after dosing with acetazolamide.(3) These effects could have been due to either drug (see mechanism).

Aspirin (> 100 Mg); Salicylates/Antidiabetics, Oral

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Complex. Salicylates appear to have intrinsic glucose lowering properties via several proposed mechanisms. Also, salicylates may cause protein binding displacement of antidiabetics. Decreased renal clearance may also occur.

CLINICAL EFFECTS: Potentiation of hypoglycemic effects may be observed.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Hypoglycemic signs and blood glucose levels should be monitored. Adjust the antidiabetic dose as needed. Particular caution should be taken when salicylates are started or stopped in patients previously stabilized on antidiabetics.

DISCUSSION: Additional documentation is necessary to confirm this potential interaction.

Aspirin (>100 Mg); Salicylates/Uricosurics

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Not clearly established. Protein binding displacement is a possibility.

CLINICAL EFFECTS: May observe hyperuricemia and gout resulting from reduced uricosuric response.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Avoid chronic, moderate to high doses of salicylates.

DISCUSSION: This interaction is well documented. Occasional small doses of salicylates do not appear to inhibit the action of uricosurics.

Aspirin/Ticlopidine

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Ticlopidine inhibits adenosine diphosphate mediated platelet aggregation and aspirin inhibits arachidonic acid mediated platelet aggregation. In addition, ticlopidine potentiates the effect of aspirin-induced inhibition of collagen mediated platelet aggregation.

CLINICAL EFFECTS: Concurrent therapy may result in increased inhibition of platelet aggregation resulting in increased bleeding times and possible hemorrhage.

PREDISPOSING FACTORS: This interaction may be more significant in patients with a predisposition to bleeding, such as those with ulcers.(1) The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Concurrent therapy is indicated to reduce the incidence of subacute stent thrombosis in patients undergoing successful coronary stent implantation; however, safety of concurrent use beyond 30 days has not been established. Long-term concurrent therapy is not recommended.(1) When concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin and/or hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling.

DISCUSSION: Studies have shown that concurrent ticlopidine and aspirin therapy potentiates inhibition of collagen mediated platelet aggregation. Also, bleeding times were increased during concurrent therapy when compared to baseline, to aspirin given alone, or to ticlopidine given alone. In one study comparing concurrent therapy with aspirin given alone and ticlopidine given alone, there was an increase in hemorrhage in the group receiving concurrent therapy.

Calcium & Iron Containing Supplements/Bictegravir

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Calcium or iron containing supplements may bind to bictegravir in the GI tract, preventing its absorption.(1)

CLINICAL EFFECTS: Calcium or iron containing supplements may reduce levels and clinical effectiveness of bictegravir.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Bictegravir and calcium or iron containing supplements may be taken together with food. Routine administration of bictegravir under fasting conditions simultaneously with, or within 2 hours after, calcium or iron containing supplements is not recommended.(1) In pregnant patients, if bictegravir is taken on an empty stomach, take bictegravir at least 2 hours before or 6 hours after calcium or iron containing supplements.(1)

DISCUSSION: Simultaneous administration of aluminum and magnesium hydroxide (20 ml) in a fasted state with bictegravir (50 mg single dose) decreased bictegravir maximum concentration (Cmax) and area-under-curve (AUC) by 80% and 79%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 2 hours after bictegravir (50 mg single dose) in a fasted state decreased bictegravir Cmax and AUC by 7% and 13%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 2 hours before bictegravir (50 mg single dose) in a fasted state decreased bictegravir Cmax and AUC by 58% and 52%, respectively.(1) Simultaneous administration of aluminum and magnesium hydroxide (20 ml) in a fed state with bictegravir (50 mg single dose) decreased bictegravir Cmax and AUC by 49% and 47%, respectively.(1) Simultaneous administration of calcium carbonate (1200 mg single dose) in a fasted state with bictegravir (50 mg single dose) decreased bictegravir Cmax and AUC by 42% and 33%, respectively.(1) Simultaneous administration of calcium carbonate (1200 mg single dose) in a fed state with bictegravir (50 mg single dose) decreased bictegravir Cmax by 10% and increased AUC 3%, respectively.(1) Simultaneous administration of ferrous fumarate (324 mg single dose) in a fasted state with bictegravir (50 mg single dose) decreased bictegravir Cmax and AUC by 71% and 63%, respectively.(1) Simultaneous administration of ferrous fumarate (324 mg single dose) in a fed state with bictegravir (50 mg single dose) decreased bictegravir Cmax and AUC by 25% and 16%, respectively.(1)

Di-; Trivalent Cations/Chloroquine; Hydroxychloroquine

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Di- and trivalent cations such as aluminum, calcium, lanthanum, and magnesium may adsorb chloroquine and hydroxychloroquine; preventing their absorption.(1-5) The adsorption may also limit the effectiveness of the di- or trivalent cation.(1)

CLINICAL EFFECTS: Simultaneous administration of di- or trivalent cations may result in decreased levels and effectiveness of chloroquine and hydroxychloroquine(2-5) and decreased effectiveness of the di- or trivalent cation.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Instruct patients to separate the administration times of these medicines by 2 to 4 hours.(2,3)

DISCUSSION: Adsorption of chloroquine by magnesium trisilicate was found to decrease hydrochloric acid uptake and decrease the amount of magnesium released in an acidic environment.(1) In a study, calcium carbonate, kaolin, and magnesium trisilicate were found to decrease the absorption of chloroquine by 52.8%, 46.5%, and 31.3%, respectively.(3) Magnesium trisilicate and magnesium oxide have been shown to decrease the release of chloroquine from tablets and to adsorb chloroquine after its release.(4) In a study in 6 subjects, magnesium trisilicate and kaolin decreased the area-under-curve (AUC) of chloroquine by 18.2% and 28.6%, respectively.(5)

Divalent & Trivalent Cations/Tetracyclines

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Di- and trivalent cations may form chelation complexes with tetracyclines, preventing their absorption.(1,2)

CLINICAL EFFECTS: Simultaneous administration of di- or trivalent cations may result in decreased levels of and therapeutics effects from tetracyclines.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Administer tetracyclines at least two hours before or after the di- or trivalent cations. When used for the treatment of H. pylori infection, tetracyclines and bismuth should be given simultaneously. The US manufacturer of omadacycline states to fast for at least four hours, administer omadacycline, and then wait four hours before taking di- or trivalent cations.(21) The US manufacturer of ferric maltose recommends separation of ferric maltose by at least 4 hours.(22)

DISCUSSION: Concurrent administration of aluminum hydroxide or divalent cations (such as calcium, magnesium, or zinc) has been shown to significantly decrease the gastrointestinal absorption of tetracycline.(3-5) Concurrent administration of tetracycline and magnesium-aluminum hydroxide gel has been shown to decrease the tetracycline area-under-curve (AUC) by 90%.(6) Magnesium-aluminum silicate has been shown to decrease the AUC of tetracycline by 27%.(7) Demeclocycline(8,9) methacycline,(10) chlortetracycline,(11) and oxytetracycline(10,12) have been shown to interact with aluminum hydroxide and/or dairy products. Doxycycline has been reported to interact with aluminum hydroxide gel.(13) Aluminum magnesium hydroxide has been shown to decrease doxycycline absorption by 84%.(14) Minocycline absorption has been shown to be impaired by aluminum, calcium, and magnesium.(15) Bismuth subsalicylate has been shown to decrease absorption of doxycycline and tetracycline by 37%(16) and 34%,(17) respectively. Since sucralfate is an aluminum salt of a sulfated disaccharide, it may also prevent absorption of tetracyclines. This complex has been used to provide site-specific delivery of tetracycline to gastric ulcers in the treatment of Helicobacter pylori gastric ulcer disease and may be useful in some indications.(18) Quinapril tablets contain a high percentage of magnesium and have been shown to decrease the absorption of tetracycline by 28-37%.(19) Lanthanum is expected to interact with tetracyclines as well.(20)

Glucosamine And-Or Chondroitin/Coumarin Anticoagulants

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: The exact mechanism is unknown, but may be the result of additive or synergistic effects on coagulation. Glucosamine is a component of heparin(1) and chondroitin is a component of danaparoid.(2) Glucosamine has been shown not to inhibit CYP2C9,(3) thus inhibition of warfarin metabolism is thought to be unlikely.

CLINICAL EFFECTS: Concurrent use of glucosamine-chondroitin may result in increased effects on coagulation, including elevated International Normalized Ratio (INR) and bleeding.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Use caution with adding or discontinuing glucosamine-chondroitin to warfarin therapy. Monitor patients receiving concurrent therapy closely for elevated INR and signs of bleeding. Patients who discontinue glucosamine-chondroitin may need their warfarin dosage adjusted to maintain therapeutic INRs. If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug.

DISCUSSION: There have been numerous reports of increased INR following the addition of glucosamine, glucosamine-chondroitin, or chondroitin alone to warfarin therapy, including 20 from the United States Food Drug Administration (US FDA), 22 from the World Health Organization (WHO), 3 from the Australian Therapeutic Goods Association (TGA), and 2 published reports. INR values typically increased between two and 20 days after the addition of glucosamine and/or chondroitin to warfarin therapy. In most cases, patients were asymptomatic; however, there were at least two reports of bleeding.(4-8) There has also been one report involving glucosamine and acenocoumarol.(9)

Nsaids; Aspirin (Non-Cardioprotective)/Beta-Blockers

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Unknown; however, possibly related to inhibition of prostaglandin by NSAIDs.

CLINICAL EFFECTS: The antihypertensive action of beta-blockers may be decreased.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Monitor patient's blood pressure and adjust the dose of the beta-blocker as needed.

DISCUSSION: Concurrent administration of beta-blockers and NSAIDs has been associated with a clinically significant loss in antihypertensive response. The magnitude of the effect of NSAIDs on control of blood pressure by beta-blockers needs to be determined for each anti-inflammatory agent. One or more of the drug pairs linked to this monograph have been included in a list of interactions that could be considered for classification as "non-interruptive" in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.

Nsaids; Aspirin (Non-Cardioprotective)/Metoprolol

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Unknown; however, possibly related to inhibition of prostaglandin by NSAIDs.

CLINICAL EFFECTS: The antihypertensive action of metoprolol may be decreased.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Monitor patient's blood pressure and adjust the dose of metoprolol as needed.

DISCUSSION: Concurrent administration of metoprolol and NSAIDs has been associated with a clinically significant loss in antihypertensive response. The magnitude of the effect of NSAIDs on control of blood pressure by beta-blockers needs to be determined for each anti-inflammatory agent. One or more of the drug pairs linked to this monograph have been included in a list of interactions that could be considered for classification as "non-interruptive" in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.

Nsaids; Salicylates/Aldosterone Receptor Antag; Baxdrostat

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: The exact mechanism is unknown; however, nonsteroidal anti-inflammatory (NSAID) inhibition of prostaglandins may allow baxdrostat, eplerenone, finerenone, or spironolactone-induced nephrotoxicity or hyperkalemia to occur in some patients.(1-4) In some patients, NSAIDs may reduce the diuretic, natriuretic and antihypertensive effects of baxdrostat, eplerenone, finerenone, or spironolactone.(1-4)

CLINICAL EFFECTS: Concurrent use of baxdrostat, eplerenone, finerenone, or spironolactone with NSAIDs may result in renal failure or hyperkalemia. The effects of the diuretic, natriuretic, or antihypertensive effects of baxdrostat, eplerenone, finerenone, or spironolactone may be decreased.(1-4)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: When possible, avoid concurrent therapy with baxdrostat, eplerenone, finerenone, or spironolactone with NSAIDs. If these agents are used concurrently, monitor renal function and serum electrolytes. If decreased renal function or hyperkalemia develops, discontinue both agents. The manufacturer of eplerenone recommends checking serum potassium and serum creatinine within 3-7 days of concurrent therapy with NSAIDs.(1) The manufacturer of spironolactone states concurrent use with NSAIDs may lead to severe hyperkalemia and extreme caution should be used during concurrent therapy.(2)

DISCUSSION: Although acute renal failure and hyperkalemia have only been reported in studies and case reports involving indomethacin, diclofenac, flurbiprofen, and ibuprofen with either triamterene or amiloride, the proposed mechanism suggests that all nonsteroidal anti-inflammatory agents may be capable of this interaction with all potassium-sparing diuretics. Patients receiving diuretics are at an increased risk of NSAID-induced renal failure.

Nsaids; Salicylates/Aliskiren

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: The exact mechanism is unknown. It is believed to be related to inhibition of prostaglandin synthesis by the NSAIDs. Use of an NSAID in combination with aliskiren, whose hypotensive effects may be related to the increase in hypotensive prostaglandins, may negate any decrease in blood pressure.

CLINICAL EFFECTS: Concurrent use of aliskiren with NSAIDs may result in decreased antihypertensive effects. In patients with existing renal impairment, the use of these agents together may also result in further deterioration of renal clearance caused by renal hypoperfusion.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Patients maintained on aliskiren should be monitored for a loss of blood pressure control and a change in renal function if an NSAID is added to their regimen. Patients receiving concurrent therapy may require higher doses of aliskiren. If blood pressure control cannot be achieved or if the patient's renal function deteriorates, the NSAID may need to be discontinued. Patients should be monitored for hypotension if NSAIDs are withdrawn from concurrent aliskiren therapy.

DISCUSSION: Indomethacin has been shown to inhibit the antihypertensive effect of captopril, cilazapril, enalapril, losartan, perindopril, and valsartan. Ibuprofen has been shown to decrease the antihypertensive effects of captopril. Two separate case reports describe individuals suspected of ACEI-associated angioedema precipitated by NSAIDs. Both cases reported symptom resolution after cessation of the NSAID. Studies have shown that sulindac does not affect the antihypertensive effects of captopril and enalapril.

Nsaids; Salicylates/Angiotensin Ii Receptor Blocker (Arb)

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Angiotensin II receptor blockers (ARBs) can cause vasodilation of the efferent renal arteriole which may result in decreased glomerular filtration rate. NSAIDs inhibit prostaglandin synthesis which can lead to afferent arteriolar vasoconstriction and may negate any decrease in blood pressure.

CLINICAL EFFECTS: Concurrent use of ARBs with NSAIDs may result in decreased antihypertensive effects. In patients with existing renal impairment, the use of these agents together may also result in further deterioration of renal clearance caused by renal hypoperfusion. Concurrent use of ARBs with NSAIDs and diuretics may result in increased risk of acute kidney injury (AKI).

PREDISPOSING FACTORS: Low water intake/dehydration, drug sensitivity, greater than 75 years of age, and use of diuretics can lead to hypovolemia and increased risk of AKI.

PATIENT MANAGEMENT: Patients maintained on ARBs should be monitored for a loss of blood pressure control and a change in renal function if an NSAID is added to their regimen. Patients receiving concurrent therapy may require higher doses of ARBs. If blood pressure control cannot be achieved or if the patient's renal function deteriorates, the NSAID may need to be discontinued. Patients should be monitored for hypotension if NSAIDs are withdrawn from concurrent ARB therapy. Concurrent use of ARBs with NSAIDs and diuretics should be used with caution and monitored for signs of AKI.

DISCUSSION: In a computational study, the risk of AKI using triple therapy (combination of a diuretic, renin-angiotensin system (RAS) inhibitor, and NSAID) was assessed. The study found the following factors may increase an individual's susceptibility to AKI: low water intake, drug sensitivity, greater than 75 years of age, and renal impairment.(22,23) In an observational study, current use of a triple therapy combination was associated with an increased rate of acute kidney injury (rate ratio (RR) 1.31, 95% confidence interval (CI) 1.12-1.53). The highest risk of AKI associated with triple therapy were observed in the first 30 days of use (RR 1.82, CI 1.35-2.46).(24) In a population based cohort study, the concurrent use of NSAIDs with renin-angiotensin system (RAS) inhibitors in 5,710 hypertensive patients stabilized on antihypertensive therapy required hypertension treatment intensification. Adjusted hazard ratios (HR) for hypertension treatment intensification were 1.34 [95% CI 1.05-1.71] for NSAIDs in general, 1.79 (95% CI 1.15-2.78) for diclofenac and 2.02 (95% CI 1.09-3.77) for piroxicam. There were significant interactions between NSAIDs and angiotensin converting enzyme inhibitors (ACE inhibitors; HR 4.09, 95% CI 2.02-8.27) or angiotensin receptor blockers (ARBs; HR 3.62, 95% CI 1.80-7.31), but not with other antihypertensive drugs.

Nsaids; Salicylates/Drospirenone

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Drospirenone has antimineralocorticoid activity and may cause hyperkalemia. NSAIDs may also increase potassium levels.(1)

CLINICAL EFFECTS: Concurrent use of drospirenone and NSAIDs may result in hyperkalemia.(1)

PREDISPOSING FACTORS: Renal insufficiency, hepatic dysfunction, adrenal insufficiency, and use of potassium supplements, ACE inhibitors, angiotensin II receptor antagonists, heparin, and potassium-sparing diuretics may increase potassium levels.(1)

PATIENT MANAGEMENT: Patients receiving drospirenone with a NSAID should have their serum potassium level checked during the first treatment cycle.(1)

DISCUSSION: Drospirenone has antimineralocorticoid activity comparable to 25 mg of spironolactone and may result in hyperkalemia. Concurrent use of NSAIDs may also increase potassium levels.(1) Occasional or chronic use of NSAIDs was not restricted in clinical trials of drospirenone.(1)

Nsaids; Salicylates/Lithium

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Decreased renal excretion of lithium, possibly resulting from NSAID-induced prostaglandin inhibition.

CLINICAL EFFECTS: May observe increased lithium toxicity.

PREDISPOSING FACTORS: Risk factors for lithium toxicity include: renal impairment or worsening of existing renal disease, dehydration, low sodium diet, and concomitant use of multiple medications which may impair renal elimination of lithium (e.g. ARBs, ACE Inhibitors, NSAIDs, diuretics). Patients who require higher therapeutic lithium levels to maintain symptom control are particularly susceptible to these factors.

PATIENT MANAGEMENT: The magnitude of this interaction is highly variable. Patients with predisposing factors, e.g. dehydration, renal impairment, or concurrent use of other agents which may impair lithium elimination, are expected to have a higher risk for lithium toxicity. If both drugs are administered, monitor plasma lithium levels and observe the patient for signs and symptoms of lithium toxicity or changes in renal function. Full effects of the addition or an increase in NSAID dose may not be seen for one to two weeks. Adjust the dose of lithium accordingly. If lithium is to be started in a patient stabilized on chronic NSAID therapy, consider starting with a lower lithium dose and titrate slowly as half-life may be prolonged. Monitor lithium concentrations until stabilized on the combination. Counsel the patient to contact their prescriber before starting an OTC NSAID. Assure that patients are familiar with signs and symptoms of lithium toxicity (e.g. new or worsening tremor, nausea/vomiting, diarrhea, ataxia, or altered mental status) and to report signs and symptoms of toxicity.

DISCUSSION: Numerous studies and case reports have been documented that administration of a NSAID to a patient stabilized on lithium therapy may result in increased serum lithium levels and possible toxicity. Full effects may take 1 to 2 weeks to develop and may persist for a week after the NSAID is discontinued.

Nsaids; Salicylates/Loop Diuretics

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: During concurrent administration of a loop diuretic and a nonsteroidal anti-inflammatory drug (NSAID), patients may retain sodium as a result of NSAID-induced prostaglandin inhibition.

CLINICAL EFFECTS: The pharmacological effects of loop diuretics may be decreased due to reduced antihypertensive and diuretic actions. Concurrent use of NSAIDs with loop diuretics and renin-angiotensin system (RAS) inhibitors may result in increased risk of acute kidney injury (AKI).

PREDISPOSING FACTORS: Low water intake/dehydration, drug sensitivity, greater than 75 years of age, and renal impairment may increase an individuals susceptibility to AKI.

PATIENT MANAGEMENT: Monitor patients for a decrease in the effects of the loop diuretic. It may be necessary to administer a higher dose of the diuretic or an alternative anti-inflammatory agent. Concurrent use of NSAIDs with loop diuretics and RAS inhibitors should be used with caution and monitored closely for signs of AKI.

DISCUSSION: In a computational study, the risk of AKI using triple therapy with a diuretic, RAS inhibitor, and NSAID was assessed. The study found the following factors may increase an individual's susceptibility to AKI: low water intake, drug sensitivity, greater than 75 years of age, and renal impairment.(19,20) In an observational study, current use of a triple therapy with a diuretic, RAS inhibitor, and NSAID, was associated with an increased rate of acute kidney injury (rate ratio (RR) 1.31, 95% confidence interval (CI) 1.12-1.53). The highest risk of AKI associated with triple therapy were observed in the first 30 days of use (RR 1.82, CI 1.35-2.46). (21) Administration of indomethacin alone has been reported to decrease sodium excretion and increase blood pressure. In patients receiving a loop diuretic (e.g., bumetanide, furosemide), these effects interfere with clinical management. Several NSAIDs have been shown to interact with loop diuretics interfering with the pharmacological effects of the diuretic. In volunteers on sodium restricted diets, ibuprofen and indomethacin inhibited furosemide diuresis.

Nsaids; Salicylates/Minoxidil

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Oral minoxidil functions as a direct-acting peripheral vasodilator, lowering elevated systolic and diastolic blood pressure by reducing resistance in peripheral blood vessels. This triggers a compensatory increase in cardiac output and renin secretion and results in sodium and water retention. NSAIDs inhibit prostaglandin synthesis and also result in sodium and water retention.(1,2)

CLINICAL EFFECTS: The risk of heart failure may increase with oral minoxidil and NSAIDs due to their combined effects on blood vessel dilation, fluid retention, and altered sodium balance. Minoxidil efficacy may be compromised.(1,2)

PREDISPOSING FACTORS: Higher doses of oral minoxidil have been associated with serious adverse events, including hypotensive syncope, pericarditis, pericardial effusion, and myocardial infarction.(1-5)

PATIENT MANAGEMENT: Closely monitor body weight, fluid and electrolyte balance, and blood pressure when using oral minoxidil and NSAIDs concurrently. Minoxidil tablets should be co-administered with an appropriate diuretic to prevent fluid retention and potential congestive heart failure. A high-ceiling (loop) diuretic is often necessary alongside vigilant monitoring of body weight. Without concurrent diuretic use, minoxidil may lead to the retention of salt and water within a few days.(1,2)

DISCUSSION: While the manufacturer of minoxidil does not provide specific recommendations regarding NSAID co-administration, it emphasizes the necessity of combining minoxidil with a beta-blocker to prevent tachycardia and increased myocardial workload. Additionally, concurrent use with a diuretic is recommended to avert serious fluid accumulation and potential congestive heart failure. NSAID labeling warns about fluid retention, edema, an elevated risk of heart failure, and potential drug interactions with beta-blockers and diuretics which can result in a blunting of the antihypertensive and cardiovascular effects of these agents.(1-5)

Nsaids; Salicylates/Sparsentan

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Sparsentan is an endothelin and angiotensin II receptor antagonist.(1) Angiotensin II receptor blockers can cause vasodilation of the efferent renal arteriole which may result in decreased glomerular filtration rate. NSAIDs inhibit prostaglandin synthesis which can lead to afferent arteriolar vasoconstriction.

CLINICAL EFFECTS: Concurrent use of sparsentan with NSAIDs (including selective COX-2 inhibitors) may result in renal hypoperfusion and deterioration of renal clearance, including possible acute kidney injury (AKI). These effects are usually reversible.(1)

PREDISPOSING FACTORS: Patients older than 75 years old, with renal artery stenosis, chronic kidney disease, severe congestive heart failure, or volume depletion (including from diuretic use and dehydration) may be at greater risk for AKI.(1-3)

PATIENT MANAGEMENT: Monitor for signs of worsening renal function if an NSAID (including selective COX-2 inhibitors) is used concurrently with sparsentan. If renal function deteriorates, the NSAID may need to be discontinued.(1)

DISCUSSION: In a computational study, the risk of AKI using triple therapy with a diuretic, renin-angiotensin system (RAS) inhibitor, and NSAID was assessed. The study found the following factors may increase an individual's susceptibility to AKI: low water intake, drug sensitivity, greater than 75 years of age, and renal impairment.(2,3) In an observational study, current use of a triple therapy combination was associated with an increased rate of acute kidney injury (rate ratio (RR) 1.31, 95% confidence interval (CI) 1.12-1.53). The highest risk of AKI associated with triple therapy were observed in the first 30 days of use (RR 1.82, CI 1.35-2.46).(4)

Nsaids; Salicylates/T Cell Immunotherapies

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: NSAIDs augment the immune system. Concurrent use with NSAIDs may interfere with the activity of CAR-T cell immunotherapies.(1)

CLINICAL EFFECTS: NSAIDs may decrease the efficacy of CAR-T cell immunotherapies.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: NSAIDs should be used with caution with or after CAR-T cell immunotherapy.(1)

DISCUSSION: An in vitro study showed aspirin and celecoxib negatively affected CD19.CAR-T cells through their effects on the induction of apoptosis, reduction of activation, and impairment of proliferation.(1)

Oral Calcium Products/Estramustine

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Calcium may bind to estramustine in the gastro-intestinal tract, preventing its absorption.(1-4)

CLINICAL EFFECTS: Simultaneous administration of oral calcium products may result in decreased levels and clinical effectiveness of estramustine.(1-4)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The UK(1) and US(2) manufacturers of estramustine state that calcium containing products should not be taken simultaneously with estramustine. One Australian manufacturer of calcium carbonate recommends separating administration by at least 3 hours.(3)

DISCUSSION: In a randomized, cross-over study in 6 patients, simultaneous administration of estramustine (420 mg) with milk (200 ml containing 120 mg calcium) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of estromustine (a metabolite of estramustine) by 59% and 68%, respectively. The AUC of estrone (another estramustine metabolite) was decreased by 63%.(4)

Oral Calcium Products/Strontium

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Calcium may prevent the absorption of strontium.(1,2)

CLINICAL EFFECTS: Simultaneous administration of strontium with oral calcium products may result in decreased levels and effectiveness of strontium.(1,2)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The administration of strontium and oral calcium products should be separated by at least 2 hours.(1,2)

DISCUSSION: Simultaneous administration of strontium with calcium or food decreased the bioavailability of strontium by 60-70% when compared to administration 3 hours after a meal.(1,2)

Oral Multivalent Cations/Oral Bisphosphonates

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Multivalent cations may bind to and inhibit the absorption of oral bisphosphonates.(1-6)

CLINICAL EFFECTS: Simultaneous administration of products containing multivalent cations may result in decreased levels of and clinical effects from oral bisphosphonates.(1-6)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Instruct patients to separate the administration times of products containing multivalent cations and oral bisphosphonates. Manufacturer recommendations regarding the separation of administration times of oral bisphosphonates and multivalent cations vary. Do NOT give multivalent cation-containing products: - until at least 30 minutes after taking alendronate(1) - within 2 hours of etidronate(2) - until at least 1 hour after taking ibandronate(3) - until at least 30 minutes after taking risedronate(4) - within 2 hours of tiludronate(5)

DISCUSSION: Multivalent cations may bind to and inhibit the absorption of oral bisphosphonates, resulting in decreased levels of and clinical effects from these agents.(1-6) Administration of aluminum- or magnesium-containing antacids 1 hour before tiludronate decreased the bioavailability of tiludronate by 60%.(5)

Polyvalent Cations And Phosphate Binders/Vadadustat

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Vadadustat may form a chelate with iron supplements, phosphate binders, and other medicinal products whose primary component consists of polyvalent cations such as aluminum, calcium, magnesium, selenium, and zinc.(1)

CLINICAL EFFECTS: Simultaneous administration of vadadustat and polyvalent cations and phosphate binders decreases the exposure and effectiveness of vadadustat.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The manufacturer of vadadustat states that it should be administered at least 1 hour before or 2 hours after any medications or products whose primary component consists of iron, phosphate binders and polyvalent cations.(1)

DISCUSSION: Two studies evaluating the pharmacokinetics, safety, and tolerability of a single oral dose of vadadustat coadministered with a phosphate binder or iron supplement were conducted in healthy adult participants. Vadadustat exposure was reduced by coadministration with sevelamer carbonate, calcium acetate, ferric citrate, and ferrous sulfate. Geometric least squares mean ratios for area under the concentration-time curve (AUC) were reduced 37% to 55% by phosphate binders and 46% by ferrous sulfate. However, when vadadustat was administered 1 hour before phosphate binders, 90% confidence intervals for vadadustat exposure were within the no-effect boundaries of +50% to -33%, indicating that drug-drug interactions can be reduced by administering vadadustat 1 hour before phosphate binders.(2)

Polyvalent Cations/Baloxavir

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Aluminum, calcium, iron, magnesium, selenium, and zinc may form chelation compounds with baloxavir.(1)

CLINICAL EFFECTS: Simultaneous administration of products containing aluminum, calcium, iron, magnesium, selenium, and zinc may result in decreased levels of and clinical effects from baloxavir.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Avoid concurrent administration of baloxavir with cation-containing products.(1)

DISCUSSION: A significant decrease in baloxavir exposure was observed when baloxavir was coadministered with calcium, aluminum, magnesium, or iron in monkeys. No studies have been conducted in humans.(1)

Polyvalent Cations/Cabotegravir

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Cabotegravir chelates polyvalent cations such as aluminum, calcium, iron, magnesium, selenium, and zinc.(1)

CLINICAL EFFECTS: Simultaneous administration of cabotegravir and polyvalent cations may decrease the absorption and clinical effects of cabotegravir.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The US manufacturer of cabotegravir states that it should be administered at least 4 hours before or 2 hours after any medications or products containing polyvalent cations such as antacids or mineral supplements.(1)

DISCUSSION: Clinical studies have not been conducted. Prescribing information states cabotegravir levels may be decreased when coadministered with antacids containing polyvalent cations (examples include aluminum or magnesium hydroxide, calcium carbonate) suggesting cabotegravir is susceptible to chelation.(1)

Polyvalent Cations/Eltrombopag

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Eltrombopag chelates polyvalent cations such as aluminum, calcium, iron, magnesium, selenium, and zinc.(1)

CLINICAL EFFECTS: Simultaneous administration of eltrombopag and polyvalent cations may decrease the absorption and clinical effects of eltrombopag.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The US manufacturer of eltrombopag states that it should be administered at least 2 hours before or 4 hours after any medications or products containing polyvalent cations such as antacids or mineral supplements.(1)

DISCUSSION: In a crossover study in 25 healthy subjects, administration of eltrombopag with an antacid (1524 mg aluminum hydroxide/1425 mg magnesium carbonate/sodium alginate) decreased eltrombopag levels by 70%.(1,2)

Polyvalent Cations/Penicillamine, Oral

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Penicillamine chelates with polyvalent cations such as aluminum, calcium, iron, magnesium, and zinc in the GI tract reducing the absorption of the penicillamine.

CLINICAL EFFECTS: Reduced (to 30% of fasting) bioavailability of penicillamine with decreased pharmacologic response.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: In order to assure systemic absorption and maximal effectiveness from penicillamine, counsel patient to separate penicillamine by at least 1 hour before or 1 hours after any medications or products containing polyvalent cations such as antacids or mineral supplements. Monitor clinical status for decreased effectiveness and adjust the penicillamine dose if necessary.

DISCUSSION: Clinical studies with polyvalent cations have not been conducted. Multivitamins with low doses of cations including iron and zinc may decrease penicillamine absorption so insure patient is aware of the risks.

Polyvalent Cations/Roxadustat

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Roxadustat chelates polyvalent cations such as aluminum, calcium, iron, magnesium, selenium, and zinc.(1)

CLINICAL EFFECTS: Simultaneous administration of roxadustat and polyvalent cations may decrease the absorption and clinical effects of roxadustat.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The manufacturer of roxadustat states that it should be administered at least 1 hour before or 1 hour after any medications or products containing polyvalent cations such as antacids or mineral supplements.(1)

DISCUSSION: Clinical studies with polyvalent cations have not been conducted. In a study in health subjects, concurrent use of roxadustat with sevelamer carbonate or calcium acetate decreased roxadustat area-under-curve (AUC) by 67% and 46% and concentration maximum (Cmax) by 66% and 52%, respectively.(1)

Polyvalent Cations; Lanthanum; Sucralfate/Bictegravir

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Polyvalent cations, lanthanum, and sucralfate may bind to bictegravir in the GI tract, preventing its absorption.(1)

CLINICAL EFFECTS: Polyvalent cations, lanthanum and sucralfate may reduce levels and clinical effectiveness of bictegravir.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Bictegravir must be taken 2 hours before or 6 hours after polyvalent cations, lanthanum or sucralfate. Medicines containing calcium can be taken together with bictegravir if taken with food.(1) Some vitamin preparations may contain sufficient quantities of polyvalent cations to interact as well.

DISCUSSION: Simultaneous administration of aluminum and magnesium hydroxide (20 ml) in a fasted state with bictegravir (50 mg single dose) decreased bictegravir maximum concentration (Cmax) and area-under-curve (AUC) by 80% and 79%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 2 hours after bictegravir (50 mg single dose) in a fasted state decreased bictegravir Cmax and AUC by 7% and 13%, respectively.(1) Administration of aluminum and magnesium hydroxide (20 ml) 2 hours before bictegravir (50 mg single dose) in a fasted state decreased bictegravir Cmax and AUC by 58% and 52%, respectively.(1) Simultaneous administration of aluminum and magnesium hydroxide (20 ml) in a fed state with bictegravir (50 mg single dose) decreased bictegravir Cmax and AUC by 49% and 47%, respectively.(1) Simultaneous administration of calcium carbonate (1200 mg single dose) in a fasted state with bictegravir (50 mg single dose) decreased bictegravir Cmax and AUC by 42% and 33%, respectively.(1) Simultaneous administration of calcium carbonate (1200 mg single dose) in a fed state with bictegravir (50 mg single dose) decreased bictegravir Cmax by 10% and increased AUC 3%, respectively.(1) Simultaneous administration of ferrous fumarate (324 mg single dose) in a fasted state with bictegravir (50 mg single dose) decreased bictegravir Cmax and AUC by 71% and 63%, respectively.(1) Simultaneous administration of ferrous fumarate (324 mg single dose) in a fed state with bictegravir (50 mg single dose) decreased bictegravir Cmax and AUC by 25% and 16%, respectively.(1)

Salicylates/Valproic Acid

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Multiple mechanisms appear to be involved. Salicylates may displace valproic acid from plasma protein binding sites. Salicylates may also affect the metabolism of valproate by increasing conjugation and decreasing oxidation of valproic acid.

CLINICAL EFFECTS: Concurrent use of salicylates may increase the unbound fraction of serum valproic acid concentration, resulting in toxicity.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Patients receiving concurrent salicylate therapy should be observed for signs of valproic acid toxicity (e.g., ataxia, drowsiness, nystagmus, tremor). The dosage of valproic acid may need to be adjusted.

DISCUSSION: In two studies involving 6 epileptic children taking valproic acid, concurrent aspirin led to an increase in serum valproic acid free fraction and an increased half-life. Renal clearance of free valproic acid was found to decrease.(1,2) In another study involving 5 children, concurrent valproic acid and aspirin resulted in a decrease in free valproic acid clearance although total valproic acid levels did not change significantly.(3) However, one study reported that the concurrent use of valproic acid and aspirin leads to an increased excretion of valproic acid and a decreased total salicylate excretion.(4) In 3 case reports, aspirin given to children taking valproic acid resulted in valproic acid toxicity (tremor, nystagmus, truncal ataxia). There was an increase in free valproic acid levels in two cases, however, a reduction in the free fraction and the total valproic acid levels occurred in the third patient.(5) In another case report, a patient was maintained on divalproex sodium (2500 mg/day) and aspirin (325 mg/day) with a trough valproate level of 24.7 ng/ml and a total valproate level of 64.0 ng/ml. Five days after aspirin was discontinued for a procedure, trough valproate levels fell to 3.9 ng/ml and a total valproate level fell to 36.0 ng/ml with no change in divalproex dosing.(6) In a study in 7 healthy males, concurrent diflunisal (250 mg twice daily) increased the unbound fraction of valproic acid (200 mg twice daily) by 20%. The area-under-curve (AUC) of 3-oxo-valproic acid increased by 35%. There were no effects on diflunisal levels.(7)

Sel Oral Cations; Antacids; H2 Antag/Dolutegravir-Rilpivirin

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Aluminum, calcium, iron, lanthanum, magnesium, sucralfate, and zinc may form chelation compounds with dolutegravir.(1) Rilpivirine requires an acidic medium for absorption. Antacid or H2 antagonist induced decrease in gastric pH may result in decrease in rilpivirine absorption.(1)

CLINICAL EFFECTS: Simultaneous administration or administration of products containing aluminum, calcium, iron, lanthanum, magnesium, and/or sucralfate close to the administration time of dolutegravir may result in decreased absorption and clinical effectiveness of dolutegravir.(1) Simultaneous administration of an antacid or a H2 antagonist may result in decreased levels and effectiveness of rilpivirine, as well as the development of resistance.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: If possible, avoid concurrent therapy with dolutegravir-rilpivirine and cation-containing products. If it is necessary to use these agents concurrently, dolutegravir-rilpivirine should be administered 4 hours before or 6 hours after taking these medications.(1) Alternatively, dolutegravir-rilpivirine and supplements containing calcium or iron can be taken together with food.(1) In patients maintained on dolutegravir-rilpivirine, administer dolutegravir-rilpivirine at least 4 hours before or 6 hours after antacids .(1) In patients maintained on dolutegravir-rilpivirine, administer dolutegravir-rilpivirine at least 4 hours before or 12 hours after H2 antagonists.(1) Concurrent use of proton pump inhibitors will dolutegravir-rilpivirine is contraindicated.(1)

DISCUSSION: In a study in 16 subjects, the administration of an antacid (Maalox - aluminum and magnesium hydroxide) simultaneously with dolutegravir (50 mg single dose) decreased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of dolutegravir by 72%, 74%, and 74%, respectively.(1) In a study in 16 subjects, the administration of an antacid (Maalox - aluminum and magnesium hydroxide) 2 hours after dolutegravir (50 mg single dose) decreased dolutegravir Cmax, AUC, and Cmin by 18%, 26%, and 30%, respectively.(1) In a study in 16 subjects, the administration of a multiple vitamin (One-A-Day) simultaneously with dolutegravir (50 mg single dose) decreased dolutegravir Cmax, AUC, and Cmin by 35%, 33%, and 32%, respectively.(1) In a study in 16 subjects, omeprazole (20 mg daily) decreased the Cmax, AUC, and Cmin of rilpivirine (150 mg daily) by 40%, 40%, and 33%, respectively. The Cmax and AUC of omeprazole decreased by 14% and 14%, respectively.(1) In a study in 24 subjects, famotidine (40 mg single dose) administered 12 hours before a single dose of rilpivirine (150 mg) had no significant effect on rilpivirine Cmax or AUC.(1) In a study in 23 subjects, famotidine (40 mg single dose) administered 2 hours before a single dose of rilpivirine (150 mg) decreased the rilpivirine Cmax and AUC by 85% and 76%, respectively.(1) In a study in 24 subjects, famotidine (40 mg single dose) administered 4 hours before a single dose of rilpivirine (150 mg) increased the rilpivirine Cmax and AUC by 21% and 13%, respectively.(1)

Selected Anticoagulants; Antiplatelets/Ibrutinib

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Ibrutinib administration lowers platelet count in the majority of patients.(1,2) In addition, ibrutinib has been shown to inhibit collagen-mediated platelet aggregation.(3-4) Bleeding has been reported with the use of ibrutinib,(1-4) anticoagulants, or antiplatelets alone.

CLINICAL EFFECTS: Concurrent use of ibrutinib with either anticoagulants or antiplatelets may increase the risk of hemorrhage.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: The Canadian product monograph for ibrutinib recommends concurrent use with anticoagulants or antiplatelets should be approached with caution. If therapeutic anticoagulation is required, consider temporarily withholding ibrutinib therapy until stable anticoagulation in achieved.(2) The US prescribing information for ibrutinib states patients receiving concurrent therapy with ibrutinib and anticoagulants and/or antiplatelets should be closely monitored for changes in platelet count or in International Normalized Ratio (INR). Carefully weigh the risks vs. benefits of concurrent therapy in patients with significant thrombocytopenia. If a bleeding event occurs, follow manufacturer instructions for ibrutinib dose adjustment.(1) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory tests (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug.

DISCUSSION: Bleeding has been reported with ibrutinib alone.(1-3) Across 27 clinical trials, grade 3 or higher bleeding events, e.g. subdural hematoma, gastrointestinal bleeding or hematuria, have occurred in up to 4% of patients, with 0.4% fatality. Grade 3 or 4 thrombocytopenia occurred in 5-19% of patients. Bleeding events of any grade occurred in 39% of patients treated with ibrutinib.(1) Concurrent use of anticoagulants or antiplatelets has been reported to increase the risk for major bleeding. In clinical trials, major bleeding occurred in 3.1% of patients taking ibrutinib without concurrent anticoagulants or antiplatelets, 4.4% of patients on concurrent antiplatelets with or without anticoagulants, and 6.1% of patients on concurrent anticoagulants with or without antiplatelets.(1) In an open-label, phase 2 trial of patients with relapsed/refractory mantle cell lymphoma on ibrutinib, 61 patients (55%) on concurrent anticoagulants or antiplatelets had a higher rate of bleeding (69% any grade, 8% grade 3-4) than patients not on anticoagulants or antiplatelets (28% any grade, 4% grade 3-4).(5) A retrospective trial found a hazard ratio of 20 (95% CI, 2.1-200) for patients on ibrutinib with concurrent anticoagulants and antiplatelets. There was a trend towards an increased bleeding risk in patients on either anticoagulants or antiplatelets, but this was not statistically significant on multivariate analysis.(6) A case report of 2 patients with chronic lymphocytic leukemia (CLL) on ibrutinib and dabigatran demonstrated no stroke nor bleeding events during the mean 11.5 month follow-up.(7) A case report of 4 patients with lymphoproliferative disease on concurrent dabigatran and ibrutinib demonstrated no stroke nor major bleeding events. 1 patient experienced grade 2 conjunctival hemorrhage whilst on both ibrutinib and dabigatran. The anticoagulant was withheld and successfully re-initiated at a lower dose with no further bleeding events.(8)

Selected Minerals, Oral/Trientine

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Mineral supplements may bind to trientine and block its absorption.

CLINICAL EFFECTS: The levels and clinical effects of trientine may be decreased.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The US manufacturer of trientine states that mineral supplements should not be given with trientine. If concomitant therapy is necessary, take trientine on an empty stomach and separate administration at least one hour apart from any other drug. Monitor clinical status for decreased effectiveness and adjust the trientine dose if necessary.

DISCUSSION: Multivitamins with minerals may decrease trientine absorption so ensure patient is aware of the risks and counsel on instructions for concurrent use.

Selected Nephrotoxic Agents/Cisplatin

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: The nephrotoxic effects of aminoglycosides or non-steroidal anti-inflammatory drugs (NSAIDs) may be additive to those of cisplatin.

CLINICAL EFFECTS: The concurrent administration of amikacin, gentamicin, tobramycin, or NSAIDs with cisplatin may result in additive nephrotoxic effects.(1,2,5,6)

PREDISPOSING FACTORS: Pre-existing renal insufficiency, advanced age, dehydration may increase the risk of nephrotoxicity.(1,5,6)

PATIENT MANAGEMENT: The US labeling for aminoglycosides and cisplatin states that the concurrent use of aminoglycosides and cisplatin should be avoided.(1,3,4,6) Inform patients that concurrent cisplatin and aminoglycosides or NSAIDs can cause nephrotoxicity and that renal function and electrolyte monitoring during treatment is necessary.(2)

DISCUSSION: The US manufacturers of amikacin, gentamicin and tobramycin state that since the nephrotoxic effects of these medications may be additive, avoid concurrent or sequential use of other neurotoxic and/or nephrotoxic agents including cisplatin.(1,3,6)

Selected Nsaids/Snris

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Serotonin release by platelets plays a role in hemostasis.(1,2) The increased risk of bleeding may be a result of a decrease in serotonin reuptake by platelets.

CLINICAL EFFECTS: Concurrent use of a serotonin-norepinephrine reuptake inhibitor(1-3) and a NSAID may result in bleeding.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Serotonin-norepinephrine reuptake inhibitors(1-3) and NSAIDs should be used concurrently with caution. Patients should be warned about the increased risk of bleeding and be educated about signs and symptoms of bleeding.(1-4) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. Discontinue anti-platelet agents in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling.

DISCUSSION: In a retrospective review of 5 years of data from the Pharmaco-Epidemiologic Prescription Database, hospitalizations for upper gastro-intestinal bleeding in antidepressant users were compared to those in non-antidepressant users. The risk of a bleed in a patient using an NSAID only based on an observed-expected ratio was 4.5 and in a patient using low-dose aspirin only was 2.5. Concurrent use of a selective serotonin reuptake inhibitor with NSAIDs or low-dose aspirin increased the risk of bleeding to 12.2 and 5.2, respectively.(4) In another study, there were 16 cases of upper gastrointestinal bleeding in patients receiving concurrent therapy with selective serotonin reuptake inhibitors and NSAIDs. Adjusted relative risk of bleeding with NSAIDs, selective serotonin reuptake inhibitors, or both were 3.7, 2.6, or 15.6, respectively.(5)

Selected Nsaids/Ssris; Vilazodone

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Serotonin release by platelets plays a role in hemostasis.(1,2) The increased risk of bleeding may be a result of a decrease in serotonin reuptake by platelets.

CLINICAL EFFECTS: Concurrent use of a SSRI(1-8) or vilazodone(9) and a NSAID may result in bleeding.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with multiple disease-associated factors (e.g. thrombocytopenia, advanced liver disease). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g., anticoagulants, antiplatelets, or corticosteroids. Risk of GI bleed may be increased in patients who are of older age, in poor health status, or who use alcohol or smoke. Risk may also be increased with longer duration of NSAID use and prior history of peptic ulcer disease and/or GI bleeding. Renal impairment has been associated with an elevated risk of GI bleed in patients on SSRIs.(13)

PATIENT MANAGEMENT: Selective serotonin reuptake inhibitors(1-8) or vilazodone(9) and NSAIDs should be used concurrently with caution. Patients should be warned about the increased risk of bleeding and be educated about signs and symptoms of bleeding.(1-10) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. Discontinue anti-platelet agents in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling.

DISCUSSION: In a retrospective review of 5 years of data from the Pharmaco-Epidemiologic Prescription Database, hospitalizations for upper gastro-intestinal bleeding in antidepressant users were compared to those in non-antidepressant users. The risk of a bleed in a patient using an NSAID only based on an observed-expected ratio was 4.5 and in a patient using low-dose aspirin only was 2.5. Concurrent use of a SSRI with NSAIDs or low-dose aspirin increased the risk of bleeding to 12.2 and 5.2, respectively.(10) In another study, there were 16 cases of upper gastrointestinal bleeding in patients receiving concurrent therapy with selective serotonin reuptake inhibitors and NSAIDs. Adjusted relative risk of bleeding with NSAIDs, selective serotonin reuptake inhibitors, or both were 3.7, 2.6, or 15.6, respectively.(11)

Selected Nsaids; Salicylates/Ace Inhibitors

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: NSAIDs inhibit prostaglandin synthesis which can lead to afferent arteriolar vasoconstriction and decreased renal blood flow. ACE inhibitors can cause vasodilation of the efferent renal arteriole which may result in decreased glomerular filtration rate.

CLINICAL EFFECTS: Concurrent use of ACE inhibitors with NSAIDs may result in decreased antihypertensive effects. In patients with existing renal impairment, the use of these agents together may also result in further deterioration of renal clearance caused by renal hypoperfusion. Concurrent use of ACE inhibitors with NSAIDs and diuretics may result in increased risk of acute kidney injury (AKI).

PREDISPOSING FACTORS: Low water intake/dehydration, drug sensitivity, greater than 75 years of age, and renal impairment may increase an individuals susceptibility to AKI.

PATIENT MANAGEMENT: Patients maintained on ACE inhibitors should be monitored for a loss of blood pressure control and a change in renal function if an NSAID is added to their regimen. Patients receiving concurrent therapy may require higher doses of ACE inhibitors. If blood pressure control cannot be achieved or if the patient's renal function deteriorates, the NSAID may need to be discontinued. Patients should be monitored for hypotension if NSAIDs are withdrawn from concurrent ACE inhibitor therapy. Concurrent use of ACE inhibitors with NSAIDs and diuretics should be used with caution and monitored closely for signs of AKI.

DISCUSSION: In a computational study, the risk of AKI using triple therapy (combination of a diuretic, renin-angiotensin system (RAS) inhibitor, and NSAID) was assessed. The study found the following factors may increase an individual's susceptibility to AKI: low water intake, drug sensitivity, greater than 75 years of age, and renal impairment.(30,31) In an observational study, current use of a triple therapy combination was associated with an increased rate of acute kidney injury (rate ratio (RR) 1.31, 95% confidence interval (CI) 1.12-1.53). The highest risk of AKI associated with triple therapy were observed in the first 30 days of use (RR 1.82, CI 1.35-2.46).(32) Indomethacin has been shown to inhibit the antihypertensive effect of captopril, cilazapril, enalapril, losartan, perindopril, and valsartan. Ibuprofen has been shown to decrease the antihypertensive effects of captopril. Two separate case reports describe individuals suspected of ACEI-associated angioedema precipitated by NSAIDs. Both cases reported symptom resolution after cessation of the NSAID. Studies have shown that sulindac does not affect the antihypertensive effects of captopril and enalapril. One or more of the drug pairs linked to this monograph have been included in a list of interactions that could be considered for classification as "non-interruptive" in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.

Selected Nsaids; Salicylates/Triamterene; Amiloride

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: The exact mechanism is unknown; however, nonsteroidal anti-inflammatory (NSAID) inhibition of prostaglandins may allow triamterene or amiloride- induced nephrotoxicity or hyperkalemia to occur in some patients.

CLINICAL EFFECTS: Possible renal failure or hyperkalemia.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: When possible, avoid concurrent therapy with triamterene or amiloride with NSAIDs. If these agents are used concurrently, monitor renal function and serum electrolytes. If decreased renal function or hyperkalemia develops, discontinue both agents.

DISCUSSION: Although acute renal failure and hyperkalemia have only been reported in studies and case reports involving indomethacin, diclofenac, flurbiprofen, and ibuprofen with either triamterene or amiloride, the proposed mechanism suggests that all nonsteroidal anti-inflammatory agents may be capable of this interaction. Patients receiving diuretics are at an increased risk of NSAID-induced renal failure.

Selected Oral Cations/Dolutegravir

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Aluminum, calcium, iron, lanthanum, magnesium, sucralfate, and zinc may form chelation compounds with dolutegravir.(1)

CLINICAL EFFECTS: Simultaneous administration or administration of products containing aluminum, calcium, iron, lanthanum, magnesium, and/or sucralfate close to the administration time of dolutegravir may result in decreased absorption and clinical effectiveness of dolutegravir.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: If possible, avoid concurrent therapy with dolutegravir and cation-containing products. If it is necessary to use these agents concurrently, dolutegravir should be administered 2 hours before or 6 hours after taking these medications.(1) Alternatively, dolutegravir and supplements containing calcium or iron can be taken together with food.(1)

DISCUSSION: In a study in 16 subjects, the administration of an antacid (Maalox - aluminum and magnesium hydroxide) simultaneously with dolutegravir (50 mg single dose) decreased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of dolutegravir by 72%, 74%, and 74%, respectively.(1) In a study in 16 subjects, the administration of an antacid (Maalox - aluminum and magnesium hydroxide) 2 hours after dolutegravir (50 mg single dose) decreased dolutegravir Cmax, AUC, and Cmin by 18%, 26%, and 30%, respectively.(1) In a study in 16 subjects, the administration of a multiple vitamin (One-A-Day) simultaneously with dolutegravir (50 mg single dose) decreased dolutegravir Cmax, AUC, and Cmin by 35%, 33%, and 32%, respectively.(1)

Selected Oral Cations/Elvitegravir

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: The exact mechanism is unknown, but aluminum, calcium, iron, lanthanum, magnesium, sucralfate, and zinc may bind to elvitegravir in GI tract.

CLINICAL EFFECTS: Simultaneous administration or administration of products containing aluminum, calcium, iron, lanthanum, magnesium, and/or sucralfate may result in decreased levels and effectiveness of elvitegravir, as well as the development of resistance.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Separate the administration of elvitegravir and products containing aluminum, calcium, iron, lanthanum, magnesium, and/or sucralfate by at least 2 hours.(1) Some vitamin preparations may contain sufficient quantities of calcium and/or magnesium salts with antacid properties to interact as well.

DISCUSSION: Administration of an antacid (exact formulation not stated) 2 hours before elvitegravir (50 mg) decreased the maximum concentration (Cmax), area-under-curve (AUC), or minimum concentration (Cmin) of elvitegravir by 18%, 15%, and 10%, respectively.(1) Administration of an antacid 2 hours after elvitegravir (50 mg) decreased the Cmax, AUC, or Cmin of elvitegravir by 21%, 20%, and 20%, respectively.(1) Administration of an antacid 4 hours before elvitegravir (50 mg) decreased the Cmax and AUC of elvitegravir by 5%, and 4%, respectively.(1) Administration of an antacid 4 hours before elvitegravir (50 mg) decreased both the Cmax and AUC of elvitegravir by 2%.(1)

Selected Oral Cations/Selected Oral Quinolones

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Aluminum, calcium, iron, lanthanum, magnesium, and zinc may form chelation compounds with the quinolones.(1-40) MECHANISM OF ACTION: Aluminum, iron, lanthanum, magnesium, and zinc may form chelation compounds with the quinolones.(1-23)

CLINICAL EFFECTS: Simultaneous administration or administration of products containing aluminum, calcium, iron, lanthanum, magnesium, and/or zinc close to the administration time of an oral quinolone may result in decreased absorption and clinical effectiveness of the quinolone. CLINICAL EFFECTS: Simultaneous administration or administration of products containing aluminum, iron, lanthanum, magnesium, and/or zinc close to the administration time of an oral quinolone may result in decreased absorption and clinical effectiveness of the quinolone

PREDISPOSING FACTORS: None determined. PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: If possible, avoid concurrent therapy with quinolones and cation-containing products. If it is necessary to administer these agents concurrently, follow the manufacturers' recommendations regarding timing of administration of the quinolone and cation-containing products. Manufacturer recommendations regarding the separation of administration times of quinolones and products containing aluminum, calcium, iron, lanthanum, magnesium, and/or zinc vary: ---Do not give ciprofloxacin for at least 2 hours before or 6 hours after oral cations.(1) ---Do not give delafloxacin for at least 2 hours before or 6 hours after oral cations.(2) ---Do not give enoxacin for at least 2 hours before or 8 hours after oral cations.(3) ---Do not give levofloxacin for at least 2 hours before or 2 hours after oral cations.(4) ---Do not give nalidixic acid for at least 2 hours before or 2 hours after oral cations.(5) ---Do not give norfloxacin for at least 2 hours before or 2 hours after oral cations.(6) ---Do not give ofloxacin for at least 2 hours before or 2 hours after oral cations.(7) ---Do not give sparfloxacin for at least 4 hours before oral cations.(8) ---Do not give sitafloxacin for at least 2 hours before or 2 hours after oral cations.(9) The US manufacturer of lanthanum recommends that quinolones be taken at least 1 hour before or 4 hours after lanthanum;(10) however, it would be prudent to follow the specific quinolone manufacturers' recommendations regarding concurrent administration of cations. The US manufacturer of ferric maltose recommends separation of ferric maltose by at least 4 hours. For quinolones not listed above, separate their administration from oral cations by as much time as feasible. PATIENT MANAGEMENT: If possible, avoid concurrent therapy with quinolones and cation-containing products. If it is necessary to administer these agents concurrently, follow the manufacturers' recommendations regarding timing of administration of the quinolone and cation-containing products. Manufacturer recommendations regarding the separation of administration times of quinolones and products containing aluminum, iron, lanthanum, magnesium, and/or zinc vary: ---Do not give gatifloxacin for at least 4 hours before oral cations(1) ---Do not give gemifloxacin for at least 2 hours before or 3 hours after oral cations.(2) ---Do not give lomefloxacin for at least 2 hours before or 4 hours after oral cations.(3) ---Do not give moxifloxacin for at least 4 hours before or 8 hours after oral cations.(4) ---Do not give trovafloxacin for at least 2 hours before or after oral cations.(5) ---Do not give prulifloxacin for at least 2 hours before or 4 hours after oral cations.(23) The US manufacturer of lanthanum recommends that quinolones be taken at least 1 hour before or 4 hours after lanthanum;(6) however, it would be prudent to follow the specific quinolone manufacturers' recommendations regarding concurrent administration of cations. The US manufacturer of ferric maltose recommends separation of ferric maltose by at least 4 hours. For quinolones not listed above, separate their administration from oral cations by as much time as feasible.

DISCUSSION: Aluminum, calcium, iron, magnesium, and zinc products have been shown to form chelation compounds with quinolone antibiotics, resulting in decreased absorption of the quinolone.(1-40) Treatment failures have been reported.(11-12) In a study in 12 healthy subjects, simultaneous administration of didanosine chewable tablets, which contain aluminum and magnesium, decreased ciprofloxacin area-under-curve (AUC) and maximum concentration (Cmax) by 92% and 98%, respectively.(14) The administration of ciprofloxacin 2 hours prior to Videx chewable/dispersible tablets decreased ciprofloxacin concentrations by 26%.(15,16) In a study in healthy subjects, pretreatment with an antacid containing aluminum-magnesium hydroxide at 5-10 minutes, 2 hours, and 4 hours before a single dose of ciprofloxacin decreased ciprofloxacin AUC by 84.9%, 76.8%, and 30%, respectively. There was no effect when the antacid was administered 6 hours before or 2 hours after.(17) In a study in 12 healthy subjects, aluminum hydroxide decreased ciprofloxacin AUC by 85%.(18) In a study in patients on continuous ambulatory peritoneal dialysis, peak levels of ciprofloxacin were decreased by 67% to 92% in patients receiving aluminum-containing antacids.(19) In a study in 15 healthy subjects, simultaneous administration of calcium acetate decreased the bioavailability of ciprofloxacin by 51%.(20) In a study in 6 healthy males, simultaneous administration of calcium carbonate decreased ciprofloxacin Cmax and AUC by 40% and 43%, respectively.(21) In a study in 12 healthy subjects, calcium carbonate decreased ciprofloxacin AUC by 40%.(18) In a study in 13 healthy males, calcium carbonate had no effect on ciprofloxacin bioavailability when administered 2 hours prior to the antibiotic.(22,23) In a study in healthy males, simultaneous administration of calcium polycarbophil decreased ciprofloxacin AUC by 50%.(24) In a study in 8 healthy males, simultaneous administration of ferrous fumarate (200 mg) decreased ciprofloxacin AUC by 70%.(25) In a study in healthy subjects, ferrous gluconate decreased ciprofloxacin bioavailability by 50%; however, no significant effects were seen with iron-ovotransferrin.(26) In a study in 8 healthy subjects, ferrous sulfate decreased the Cmax and AUC of simultaneously administered ciprofloxacin by 54% and 57%, respectively.(27) In a study in 8 healthy subjects, administration of ferrous sulfate decreased the Cmax and AUC of ciprofloxacin by 33% and 46%, respectively. Administration of ferrous gluconate decreased the Cmax and AUC of ciprofloxacin by 57% and 67%, respectively. Administration of a multivitamin product containing calcium, copper, iron, magnesium, manganese, and zinc decreased the Cmax and AUC of ciprofloxacin by 53% and 56%, respectively.(28) In a study in 12 healthy males, ferrous sulfate decreased ciprofloxacin AUC by 63%.(29) In a study in 12 healthy subjects, lanthanum carbonate decreased the area-under-curve (AUC) and maximum concentration (Cmax) of concurrently administered ciprofloxacin by 54% and 56%, respectively.(30) In a study in 12 healthy males, a multivitamin containing zinc decreased ciprofloxacin AUC by 22%.(29) In a study in 12 healthy subjects, an antacid containing aluminum-magnesium hydroxide had no effect on the pharmacokinetics of intravenous enoxacin.(31) In a study in 10 healthy subjects, administration of an aluminum-magnesium hydroxide antacid 0.5 hours or 2 hours before oral enoxacin (400 mg single dose) decreased the AUC of enoxacin by 73% and 43%, respectively. There were no significant effects on enoxacin AUC when the antacid was administered 8 hours before or 2 hours after enoxacin.(32) In a study in 9 healthy subjects, colloidal aluminum phosphate had no effect on the amount of enoxacin absorbed; however, ferrous sulfate (1050 mg) decreased the amount of enoxacin absorption by 10%.(33) In a study in 5 healthy subjects and 5 patients with cystic fibrosis, separation of levofloxacin (750 mg) and calcium carbonate (500 mg 3 times daily with meals) by 2 hours resulted in no interaction in healthy subjects; however, levofloxacin levels were not bioequivalent in patients with cystic fibrosis.(34) Concurrent magnesium-aluminum hydroxide or calcium have been shown to decrease the bioavailability of norfloxacin by 91.0% and 63.5%, respectively.(35) Concurrent zinc has been shown to decrease the bioavailability of norfloxacin.(36) In a study in 8 healthy subjects, ferrous sulfate decreased the Cmax and AUC of simultaneously administered norfloxacin by 75% and 73%, respectively.(27) Simultaneous aluminum phosphate was found to decrease the rate, but not the extent, of absorption of ofloxacin.(37) In a study in 8 healthy subjects, ferrous sulfate decreased the Cmax and AUC of simultaneously administered norfloxacin by 36% and 25%, respectively.(27) In an in vitro study, ferrous sulfate, aluminum hydroxide, and calcium carbonate decreased ofloxacin availability by 32.6%, 30.7%, and 26.2%, respectively. However, in vivo tests showed a significant effect with only aluminum hydroxide.(38) In a study in 9 healthy subjects, simultaneous administration colloidal aluminum phosphate had no effect on ofloxacin (200 mg) absorption; however, ferrous sulfate (1050 mg) decreased the ofloxacin fraction of dose absorbed by 10.85%.(33) In a study in 16 subjects, administration of either aluminum-magnesium hydroxide or calcium carbonate at least 2 hours before or after ofloxacin administration had no significant effects on ofloxacin levels.(39) The administration of an antacid containing aluminum hydroxide and magnesium hydroxide 2 hours before, 2 hours after, and 4 hours after sparfloxacin decreased sparfloxacin levels by 23%, 17%, and 5%, respectively.(40) One or more of the drug pairs linked to this monograph have been included in a list of interactions that could be considered for classification as "non-interruptive" in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology. DISCUSSION: Magnesium and aluminum compounds have been shown to form chelation compounds with quinolone antibiotics, resulting in decreased absorption of the quinolone.(1-22) Treatment failures during concurrent use of cations and gatifloxacin(7) and pefloxacin(8) have been reported. In a study in 24 healthy subjects, administration of an aluminum-magnesium hydroxide antacid simultaneously, 2 hours before, or 2 hours after decreased the area-under-curve (AUC) of a single dose of gatifloxacin (400 mg) by 42%, 64%, or 18%, respectively. There were no affects on gatifloxacin AUC when the antacid was administered 4 hours after gatifloxacin.(9) In a study in 16 healthy males, administration of an aluminum-magnesium hydroxide antacid 10 minutes before or 3 hours after a single dose of gemifloxacin (320 mg) decreased the gemifloxacin AUC by 85% and 15%, respectively. There was no affect when the antacid was administered 2 hours after gemifloxacin.(10) In a study in 16 subjects, simultaneous administration of calcium carbonate decreased the maximum concentration (Cmax) and AUC of a single dose of gemifloxacin (320 mg) by 17% and 21%, respectively. There was no effect of calcium carbonate when administered either 2 hours before or after gemifloxacin.(11) In a study in 27 healthy males, the administration of ferrous sulfate (325 mg) 3 hours before a single dose of gemifloxacin (320 mg) decreased the Cmax and AUC of gemifloxacin by 20% and 11%, respectively. There were no effects when ferrous sulfate was administered 2 hours after gemifloxacin.(12) In a study in 8 healthy subjects, ferrous sulfate (100 mg elemental iron) decreased the Cmax and AUC of a single dose of lomefloxacin by 26% and 13%, respectively. There were no effects with concurrent calcium carbonate (500 mg calcium).(13) Magnesium- and aluminum-containing antacids have been shown to decrease the bioavailability of lomefloxacin by 40%.(14) Administration of moxifloxacin 2 hours before, simultaneously, or 4 hours after a magnesium- and aluminum-containing antacid decreased moxifloxacin AUC by 26%, 60%, and 23%, respectively.(15) Simultaneous administration of moxifloxacin and ferrous sulfate (100 mg) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of moxifloxacin by 39% and 59%, respectively.(16) Concurrent administration of calcium had no affect on moxifloxacin pharmacokinetics.(17) In a study in 10 healthy subjects, an aluminum-magnesium hydroxide antacid decreased the bioavailability of pefloxacin (400 mg) by 44.4%.(18) The administration of an antacid containing aluminum hydroxide and magnesium hydroxide 5 minutes before rufloxacin decreased rufloxacin levels by 36%. Administration of the antacid 4 hours after rufloxacin decreased rufloxacin levels by 13%.(19) Magnesium- and aluminum-containing antacids have been shown to decrease the bioavailability of temafloxacin by 40%.(20) Aluminum hydroxide has been shown to decrease the bioavailability of tosufloxacin by 31.6%.(21) Administration of an antacid containing aluminum hydroxide and magnesium hydroxide 30 minutes before trovafloxacin decreased trovafloxacin levels by 66%.(22) One or more of the drug pairs linked to this monograph have been included in a list of interactions that could be considered for classification as "non-interruptive" in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.

Selected Salicylates/Heparin

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Additive prolongation of bleeding time.

CLINICAL EFFECTS: Increased risk of bleeding which may extend for several days beyond discontinuation of salicylates.

PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs).

PATIENT MANAGEMENT: Avoid concomitant administration of these drugs. If this combination is used, monitor patients for signs of blood loss, including decreased hemoglobin and/or hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. A non-acetylated salicylate may be used to avoid antiplatelet activity. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. Single ingredient aspirin or buffered aspirin products with strengths < or = 325 mg and combination aspirin products which are used to treat cardiovascular disease (e.g. aspirin+statins, aspirin+dipyridamole) are not included in this interaction.

DISCUSSION: This interaction is likely to occur.

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

• Diarrhea

• Asthma
• Diabetes mellitus
• Disease of liver
• Gout
• Hemophilia
• Hypoprothrombinemia
• Increased risk of bleeding due to coagulation disorder
• Kidney disease with reduction in glomerular filtration rate (GFr)
• No disease contraindications
• Peptic ulcer

There is no enhanced messaging for this drug.

There are no severe adverse reactions for this drug.

More Frequent

• Abdominal pain with cramps
• Diarrhea
• Gastric acid hypersecretory conditions
• Heartburn
• Nausea

No enhanced messaging available.

No enhanced messaging available.

No enhanced messaging available.

No enhanced messaging available.

No enhanced messaging available.