Ibrance (palbociclib)
Antineoplastic- Cyclin-Dependent Kinase (CDK) 4/6 Inhibitors Oral Capsule; Oral Tablet
Last reviewed · Source: First Databank (FDB) drug data
Overview
Palbociclib, a reversible and selective inhibitor of cyclin-dependent kinase (CDK) 4 and 6, is an antineoplastic agent.
Palbociclib, a reversible and selective inhibitor of cyclin-dependent kinase (CDK) 4 and 6, is an antineoplastic agent. Several mechanisms contribute to the dysregulation of the cell cycle during the G1 into S phase, including amplification or overexpression of the cyclin D oncogene or the loss of intrinsic CDK inhibitors (i.e., p16, p15, p18, p19, p21, p27, p57) in breast cancer. Palbociclib specifically inhibits CDK4 and 6 and blocks the interaction of CDK4 and 6 with cyclin D, resulting in inhibition of phosphorylation of the tumor suppressor protein retinoblastoma and inhibition of progression of the cell cycle from the G1 into S phase.
In vitro, palbociclib has demonstrated reduced cellular proliferation of estrogen receptor-positive breast cancer cell lines by inhibiting the G1 into S phase of the cell cycle. Decreased phosphorylation of retinoblastoma protein resulting in reduced E2F expression and signaling and increased cell growth arrest have been reported in breast cancer cell lines treated with palbociclib and antiestrogens compared with either drug alone. In vitro, the combination of palbociclib with antiestrogens increased cell senescence for up to 6 days following discontinuance of therapy in estrogen receptor-positive breast cancer cell lines.
The combination of palbociclib and letrozole also has demonstrated increased inhibition of retinoblastoma protein phosphorylation, downstream signaling, and tumor growth compared with either drug alone in patient-derived estrogen receptor-positive breast tumor xenografts. In vitro, human bone marrow mononuclear cells treated with palbociclib with or without an antiestrogen did not become senescent and cell proliferation resumed following discontinuance of exposure.
Following oral administration, the mean absolute bioavailability of palbociclib is 46%. AUC and peak plasma concentrations of palbociclib are dose proportional over a dosage range of 25-225 mg. Peak plasma concentrations of palbociclib are achieved about 6-12 hours following oral administration of the capsules.
Peak plasma concentrations are attained 4-12 hours following oral administration of the tablets. Following repeated doses of palbociclib administered once daily, steady-state concentrations of the drug were achieved in 8 days and the median accumulation ratio for the drug was 2.4.
Absorption and systemic exposure to palbociclib capsules were decreased in approximately 13% of individuals receiving the drug in a fasting state; systemic exposure to palbociclib increased when the drug was administered with food in these individuals, but administration with food did not alter systemic exposure to a clinically important extent in other individuals. Administration of palbociclib with food reduces the interindividual variability in systemic exposure to palbociclib. Oral administration of palbociclib capsules with a low-fat, low-calorie (approximately 400-500 calories) or high-fat, high-calorie meal (approximately 800-1000 calories) resulted in increases in systemic exposure of 12 or 21%, respectively, and increases in peak plasma concentrations of 27 or 38%, respectively, compared with administration in the fasting state.
When an oral dose of palbociclib capsules was administered between 2 moderate-fat, standard-calorie meals (approximately 500-700 calories per meal) (i.e., single dose administered 1 hour after the first meal and 2 hours before the second meal), systemic exposure and peak plasma concentrations of the drug were increased by 13 and 24%, respectively, compared with administration in the fasting state. Oral administration of palbociclib tablets with a high-fat, high-calorie meal (approximately 800-1000 calories per meal) or with a moderate-fat, standard-calorie meal (approximately 500-700 calories per meal) resulted in increases in systemic exposure of 22 or 9%, respectively, and increases in peak plasma concentrations of 26 or 10%, respectively, compared with administration of the tablets in the fasting state.
Palbociclib is metabolized in the liver principally by cytochrome P-450 (CYP) isoenzyme 3A and sulfotransferase (SULT) 2A1. In vitro, palbociclib is approximately 85% bound to plasma proteins. Following oral administration of a single radiolabeled dose of palbociclib, 74.1% of the radioactivity was recovered in feces and 17.5% was recovered in urine; the majority of the dose was excreted as metabolites.
The mean plasma elimination half-life of the drug is 29 hours.
Population pharmacokinetic analyses indicate that age (22-89 years), sex, race (Asian versus non-Asian), and body weight do not have clinically important effects on the exposure of palbociclib.
USES: Palbociclib is used to treat a certain type of breast cancer. It works by slowing or stopping the growth of cancer cells.
Generic name: palbociclib
Pronunciation: (PAL-boe-SYE-klib)
Drug class: Antineoplastic- Cyclin-Dependent Kinase (CDK) 4/6 Inhibitors
Therapeutic class: Antineoplastics
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Ibrance
Indications
The following indications are listed for Ibrance:
- Hormone Receptor (Hr)-Positive, Her2-Negative Advanced Breast Cancer
- Hormone Receptor (Hr)-Positive, Her2-Negative, Pik3ca Mutated Advanced Breast Cancer
- Hormone Receptor (Hr)-Positive, Her2-Positive Breast Cancer
Also known as: Hormone Receptor (Hr)-Positive, Her2-Negative Metastatic Breast Cancer, Hormone Receptor (Hr)-Positive, Her2-Negative, Pik3ca Mutated Metastatic Breast Cancer, Hormone Receptor-Positive Her2-Positive Breast Carcinoma, Hr-Positive, Her2-Negative, Pik3ca-Mutated Advanced Breast Cancer, Hr-Positive, Human Epidermal Growth Factor Receptor 2 (Her2)-Negative Advanced Breast Cancer, Hr-Positive, Human Epidermal Growth Factor Receptor 2 (Her2)-Negative Metastatic Breast Cancer, Hr-Positive/Her2-Positive Breast Cancer.
Dosing
Management of some adverse effects may require temporary interruption of therapy, dosage reduction, and/or permanent discontinuance of palbociclib therapy. Dosage adjustment of palbociclib is recommended based on individual safety and tolerability. Up to 2 dosage reductions for toxicity may be made. If dosage modification is necessary, an initial dosage reduction to 100 mg once daily is recommended. If further dosage reduction is necessary, the dosage should be reduced to 75 mg once daily. Dosages less than 75 mg once daily are not recommended.
Palbociclib is administered orally (as capsules or tablets) once daily. The capsules should be administered with food while the tablets may be administered without regard to food at approximately the same time each day. The capsules and tablets should be swallowed intact and should not be chewed, crushed, or opened/split.
If a dose of palbociclib is missed or vomited, patients should not double the dose or take extra doses. The next dose should be taken at the regularly scheduled time.
Store palbociclib capsules and tablets at 20-25oC; excursions permitted between 15-30oC. Store tablets in their original blister pack.
| Drug label | Dosing type | Instructions |
|---|---|---|
| Ibrance 75 Mg Capsule | Maintenance | Take 1 capsule (75 mg) by oral route once daily for 21 consecutive days, followed by 7 days off. |
| Ibrance 100 Mg Capsule | Maintenance | Take 1 capsule (100 mg) by oral route once daily for 21 consecutive days, followed by 7 days off. |
| Ibrance 125 Mg Capsule | Maintenance | Take 1 capsule (125 mg) by oral route once daily for 21 consecutive days, followed by 7 days off. |
| Ibrance 75 Mg Tablet | Maintenance | Take 1 tablet (75 mg) by oral route once daily for 21 consecutive days, followed by 7 days off. |
| Ibrance 100 Mg Tablet | Maintenance | Take 1 tablet (100 mg) by oral route once daily for 21 consecutive days, followed by 7 days off. |
| Ibrance 125 Mg Tablet | Maintenance | Take 1 tablet (125 mg) by oral route once daily for 21 consecutive days, followed by 7 days off. |
No dosing information is available for this tab.
Drug interactions
Palbociclib is metabolized principally by cytochrome P-450 (CYP) isoenzyme 3A and sulfotransferase (SULT) 2A1. In vitro studies indicate that palbociclib does not inhibit CYP isoenzymes 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, and 2D6 or induce CYP isoenzymes 1A2, 2B6, 2C8, and 3A4 at clinically relevant concentrations; however, in vivo studies indicate that the drug is a weak time-dependent inhibitor of CYP3A.
In vitro studies indicate that palbociclib has a low potential for inhibition of organic cation transporter (OCT) 2, organic anion transporter (OAT) 1, OAT 3, organic anion transport protein (OATP) 1B1 and OATP1B3 at clinically relevant concentrations. In vitro studies also indicate that palbociclib has potential to inhibit P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) at clinically relevant concentrations.
Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.
Immunosuppressive; Immunomod/Cladribine Onc Inj (10 Mg/5 Ml)
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: Cladribine in combination with immunosuppressives and immune-modulators all suppress the immune system.(1-2)
CLINICAL EFFECTS: Concurrent use of cladribine with immunosuppressive or immune-modulating agents may result in an increased risk of serious infections.(1-2)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications.
PATIENT MANAGEMENT: Recommendations for cladribine regarding this interaction differ between regulatory approving agencies. The UK and AU manufacturers of Litak state that concomitant use of other myelosuppressive medicinal products with cladribine is contraindicated.(1-2) The Israeli manufacturer of Litak states that cladribine should not be used concomitantly with other myelosuppressive medicinal products.(3)
DISCUSSION: The risk of severe myelotoxicity and long-lasting immunosuppression is increased in patients with a disease-related bone marrow infiltration or a previous myelosuppressive treatment.(1-3)
Immunosuppressives; Immunomodulators/Efalizumab; Natalizumab
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: Natalizumab,(1-3) efalizumab,(4) immunosuppressives, and immunomodulators all suppress the immune system.
CLINICAL EFFECTS: Concurrent use of natalizumab(1-3) or efalizumab(4) with immunosuppressives or immunomodulators may result in an increased risk of infections, including progressive multifocal leukoencephalopathy (PML), an opportunistic infection caused by the JC virus (JCV).
PREDISPOSING FACTORS: Previous JCV infection, longer duration of natalizumab treatment - especially if greater than 2 years, and prior or concomitant treatment with immunosuppressant medication are all independent risk factors which increase the risk for PML.(1,5) The FDA has estimated PML incidence stratified by risk factors: If anti-JCV antibody positive, no prior immunosuppressant use and natalizumab treatment less than 25 months, incidence <1/1,000. If anti-JCV antibody positive, history of prior immunosuppressant use and natalizumab treatment less than 25 months, incidence 2/1,000 If anti-JCV antibody positive, no prior immunosuppressant use and natalizumab treatment 25-48 months, incidence 4/1,000 If anti-JCV antibody positive, history of prior immunosuppressant use and natalizumab treatment 25-48 months, incidence 11/1,000.
PATIENT MANAGEMENT: The US manufacturer of natalizumab states patients with Crohn's disease should not receive concurrent immunosuppressants, with the exception of limited overlap of corticosteroids, due to the increased risk for PML. For new natalizumab patients currently receiving chronic oral corticosteroids for Crohn's Disease, begin corticosteroid taper when therapeutic response to natalizumab has occurred. If corticosteroids cannot be discontinued within six months of starting natalizumab, discontinue natalizumab.(3) The US manufacturer of natalizumab states that natalizumab should not ordinarily be used in multiple sclerosis patients receiving immunosuppressants or immunomodulators due to the increased risk for PML. Immunosuppressives include, but are not limited to azathioprine, cyclophosphamide, cyclosporine, mercaptopurine, methotrexate, mitoxantrone, mycophenolate, and corticosteroids.(3,6) The UK manufacturer of natalizumab states that concurrent use with immunosuppressives or antineoplastic agents is contraindicated.(1) The Canadian manufacturer of natalizumab states that natalizumab should not be used with immunosuppressive or immunomodulatory agents.(2) The US manufacturer of certolizumab states that concurrent therapy with natalizumab is not recommended.(7)
DISCUSSION: Progressive multifocal leukoencephalopathy has been reported in patients receiving concurrent natalizumab were recently or concomitantly taking immunomodulators or immunosuppressants.(1-5,8,9) In a retrospective cohort study of multiple sclerosis patients newly initiated on a disease-modifying therapy, use of high-efficacy agents (alemtuzumab, natalizumab, or ocrelizumab) resulted in the same risk of overall infections as moderate-efficacy agents, but there was an elevated risk of serious infections (adjusted hazard ratio [aHR] = 1.24, 95% confidence interval (CI) = 1.06-1.44) and UTIs (aHR = 1.21, 95% CI = 1.14-1.30).(10)
Palbociclib/Strong Cyp3a4 Inducers
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: Agents that induce the CYP3A4 isoenzyme may induce the metabolism of palbociclib.(1)
CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inducers may decrease the levels and effectiveness of palbociclib.(1)
PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks.
PATIENT MANAGEMENT: Avoid the concurrent use of strong CYP3A4 inducers in patients receiving therapy with palbociclib.(1) Consider the use of alternatives with little to no induction potential.
DISCUSSION: In a study in 14 healthy subjects, rifampin (600 mg daily) decreased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of palbociclib by 70% and 85%, respectively.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2-3)
Selected Immunosuppressants/Nadofaragene Firadenovec
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: Nadofaragene firadenovec may contain low levels of replication-competent adenovirus.(1)
CLINICAL EFFECTS: Concurrent use of nadofaragene firadenovec in patients receiving immunosuppressive therapy may cause disseminated adenovirus infection.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: Individuals who are immunosuppressed or immune-deficient should not receive nadofaragene firadenovec.(1)
DISCUSSION: Nadofaragene firadenovec is a non-replicating adenoviral vector-based gene therapy but may contain low levels of replication-competent adenovirus. Immunocompromised persons, including those receiving immunosuppressant therapy, may be at risk for disseminated adenovirus infection.(1)
Selected Immunosuppressants/Talimogene Laherparepvec
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: Talimogene laherparepvec is a live, attenuated herpes simplex virus.(1)
CLINICAL EFFECTS: Concurrent use of talimogene laherparepvec in patients receiving immunosuppressive therapy may cause a life-threatening disseminated herpetic infection.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: Talimogene laherparepvec is contraindicated in immunosuppressed patients.(1) The magnitude of immunocompromise and associated risks due to immunosuppressant drugs should be determined by a physician.
DISCUSSION: Concurrent use of talimogene laherparepvec in patients receiving immunosuppressive therapy may cause a life-threatening disseminated herpetic infection.(1)
Weak Cyp3a4 Inhibitors/Lemborexant (> 5 Mg)
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: Inhibitors of CYP3A4 may inhibit the metabolism of lemborexant.(1)
CLINICAL EFFECTS: Concurrent use of an inhibitor of CYP3A4 may result in increased levels of and effects from lemborexant, including somnolence, fatigue, CNS depressant effects, daytime impairment, headache, and nightmare or abnormal dreams.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The maximum recommended dose of lemborexant with concurrent use of a weak CYP3A4 inhibitors should not exceed 5 mg per dose.(1) For patients on avapritinib: this interaction applies only to gastrointestinal stromal tumor (GIST) patients on avapritinib 200 mg or 300 mg.(2)
DISCUSSION: Lemborexant is a CYP3A4 substrate. In a PKPB model, concurrent use of lemborexant with itraconazole increased area-under-curve (AUC) and concentration maximum (Cmax) by 3.75-fold and 1.5-fold, respectively. Concurrent use of lemborexant with fluconazole increased AUC and Cmax by 4.25-fold and 1.75-fold, respectively.(1) Weak inhibitors of CYP3A4 include: amiodarone, amlodipine, anamorelin, asciminib, avapritinib, azithromycin, Baikal skullcap, belumosudil, berberine, bicalutamide, blueberry, brodalumab, camizestrant, cannabidiol, capivasertib, chlorzoxazone, cilostazol, cimetidine, ciprofloxacin, clotrimazole, cranberry, cyclosporine, daclatasvir, daridorexant, delavirdine, dihydroberberine, diosmin, elinzanetant, everolimus, flibanserin, fosaprepitant, fostamatinib, gepotidacin, ginkgo, givinostat, glecaprevir/pibrentasvir, goldenseal, grazoprevir, isoniazid, istradefylline, ivacaftor, lacidipine, lapatinib, larotrectinib, lazertinib, leflunomide, levamlodipine, linagliptin, lomitapide, lurasidone, mavorixafor, olaparib, osilodrostat, palbociclib, pazopanib, peppermint oil, piperine, propiverine, propofol, ranitidine, ranolazine, resveratrol, roxithromycin, rucaparib, selpercatinib, simeprevir, sitaxsentan, skullcap, teriflunomide, ticagrelor, tolvaptan, trofinetide, vepdegestrant, viloxazine, vonoprazan, and ziftomenib.(1,3)
Weak Cyp3a4 Inhibitors/Ubrogepant (> 50 Mg)
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: Weak inhibitors of CYP3A4 may inhibit the metabolism of ubrogepant.(1)
CLINICAL EFFECTS: Concurrent use of ubrogepant with weak CYP3A4 inhibitors may result in an increase in exposure of ubrogepant.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The manufacturer recommends a dosage adjustment of ubrogepant when used concomitantly with weak CYP3A4 inhibitors. Initial dose of ubrogepant should not exceed 50 mg when used concomitantly with weak inhibitors of CYP3A4. A second dose may be given within 24 hours but should not exceed 50 mg when used concurrently with weak CYP3A4 inhibitors.(1) For patients on avapritinib: this interaction applies only to gastrointestinal stromal tumor (GIST) patients on avapritinib 200 mg or 300 mg.(2)
DISCUSSION: Coadministration of ubrogepant with verapamil, a moderate CYP3A4 inhibitor, resulted in a 3.5-fold and 2.8-fold increase in area-under-curve (AUC) and concentration maximum (Cmax), respectively. No dedicated drug interaction study was conducted to assess concomitant use with weak CYP3A4 inhibitors. The conservative prediction of the maximal potential increase in ubrogepant exposure with weak CYP3A4 inhibitors is not expected to be more than 2-fold.(1) Weak inhibitors of CYP3A4 include: amiodarone, amlodipine, anamorelin, asciminib, avapritinib, azithromycin, Baikal skullcap, berberine, bicalutamide, blueberry, brodalumab, camizestrant, cannabidiol, capivasertib, chlorzoxazone, cilostazol, cimetidine, ciprofloxacin, clotrimazole, cranberry, cyclosporine, daclatasvir, delavirdine, deutivacaftor, dihydroberberine, diosmin, elinzanetant, everolimus, flibanserin, fosaprepitant, fostamatinib, gepotidacin, givinostat, glecaprevir/pibrentasvir, goldenseal, grazoprevir, isoniazid, istradefylline, ivacaftor, lacidipine, lapatinib, larotrectinib, lazertinib, leflunomide, levamlodipine, linagliptin, lomitapide, lurasidone, maribavir, mavorixafor, olaparib, osilodrostat, palbociclib, pazopanib, peppermint oil, piperine, pirtobrutinib, propiverine, propofol, ranitidine, ranolazine, resveratrol, roxithromycin, rucaparib, simeprevir, sitaxsentan, skullcap, teriflunomide, ticagrelor, tolvaptan, trofinetide, vepdegestrant, viloxazine, vonoprazan, and ziftomenib. (3,4)
Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
Immunosuppres;Immunomodul/Selected Multiple Sclerosis Agents
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Ocrelizumab or ofatumumab in combination with immunosuppressives and immune-modulators all suppress the immune system.(1,2)
CLINICAL EFFECTS: Concurrent use of ocrelizumab or ofatumumab with immunosuppressive or immune-modulating agents may result in an increased risk of serious infections, such as disseminated herpetic infection or progressive multifocal leukoencephalopathy (PML), an opportunistic infection caused by the JC virus (JCV).(1,2)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications.
PATIENT MANAGEMENT: The ocrelizumab US prescribing information states: - Ocrelizumab and other immune-modulating or immunosuppressive therapies, (including immunosuppressant doses of corticosteroids) are expected to increase the risk of immunosuppression, and the risk of additive immune system effects must be considered if these therapies are coadministered with ocrelizumab. When switching from drugs with prolonged immune effects, such as daclizumab, fingolimod, natalizumab, teriflunomide, or mitoxantrone, the duration and mode of action of these drugs must be considered to avoid unintended additive immunosuppressive effects when initiating ocrelizumab.(1) The ofatumumab US prescribing information states: - Ofatumumab and other immunosuppressive therapies (including systemic corticosteroids) may have the potential for increased immunosuppressive effects and increase the risk of infection. When switching between therapies, the duration and mechanism of action of each therapy should be considered due to the potential for additive immunosuppressive effects. Ofatumumab for MS therapy has not been studied in combination with other MS agents that suppress the immune system.(2)
DISCUSSION: Fatal disseminated herpes zoster and herpes simplex infections and cases of progressive multifocal leukoencephalopathy (PML) have been reported in patients who previously received immunomodulators or immunosuppressants.(1,2) In a retrospective cohort study of multiple sclerosis patients newly initiated on a disease-modifying therapy, use of high-efficacy agents (alemtuzumab, natalizumab, or ocrelizumab) resulted in the same risk of overall infections as moderate-efficacy agents, but there was an elevated risk of serious infections (adjusted hazard ratio [aHR] = 1.24, 95% confidence interval (CI) = 1.06-1.44) and UTIs (aHR = 1.21, 95% CI = 1.14-1.30).(3)
Immunosuppressives; Immunomodulators/Baricitinib
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Concurrent use of baricitinib with other biologic disease-modifying antirheumatic drugs (DMARDs) or potent immunosuppressants such as azathioprine or cyclosporine may result in additive or synergistic effects on the immune system.
CLINICAL EFFECTS: Concurrent use of baricitinib with other biologic DMARDs or potent immunosuppressants such as azathioprine or cyclosporine may increase the risk of serious infections.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of baricitinib states that concurrent use of baricitinib with biologic DMARDs or potent immunosuppressants is not recommended.(1)
DISCUSSION: Most patients who developed serious infections while being treated with baricitinib were on concomitant immunosuppressants like methotrexate and corticosteroids. The combination of baricitinib with other biologic DMARDs has not been studied.(1)
Immunosuppressives; Immunomodulators/Cladribine Oral
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Cladribine in combination with immunosuppressives and immune-modulators all suppress the immune system.(1-2)
CLINICAL EFFECTS: Concurrent use of cladribine with immunosuppressive or immune-modulating agents may result in an increased risk of serious infections, such as disseminated herpetic infection or progressive multifocal leukoencephalopathy (PML), an opportunistic infection caused by the JC virus (JCV).(1-2)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications.
PATIENT MANAGEMENT: Recommendations for cladribine regarding this interaction differ between regulatory approving agencies. The cladribine US prescribing information states: -Concomitant use with myelosuppressive or other immunosuppressive drugs is not recommended. Acute short-term therapy with corticosteroids can be administered. In patients who have previously been treated with immunomodulatory or immunosuppressive drugs, consider potential additive effect, the mode of action, and duration of effect of the other drugs prior to initiation of cladribine.(1) The cladribine Canadian prescribing information states: -Use of cladribine in immunocompromised patients is contraindicated because of a risk of additive effects on the immune system. Acute short-term therapy with corticosteroids can be administered during cladribine treatment.(2)
DISCUSSION: Fatal disseminated herpes zoster and herpes simplex infections and cases of progressive multifocal leukoencephalopathy (PML) have been reported in patients who previously received immunomodulators or immunosuppressants.(1-2)
Immunosuppressives; Immunomodulators/Deuruxolitinib
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Deuruxolitinib, immunosuppressives, and immunomodulators all suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of deuruxolitinib and potent immunosuppressants may increase the risk of serious infections.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of deuruxolitinib states that concurrent use of deuruxolitinib with other JAK inhibitors, biologic immunomodulators, cyclosporine or other potent immunosuppressants is not recommended.(1) If concurrent use cannot be avoided, patients should be monitored for signs and symptoms of infection. If a patient develops a serious or opportunistic infection, interrupt deuruxolitinib treatment until the infection is controlled.
DISCUSSION: Serious infections have been reported in patients receiving treatment with deuruxolitinib.(1)
Immunosuppressives; Immunomodulators/Etrasimod
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Etrasimod causes reversible sequestration of lymphocytes in lymphoid tissues, resulting in a mean 55% decrease in peripheral blood lymphocyte count at 52 weeks.(1) Other immunosuppressives and immune-modulators also suppress the immune system.
CLINICAL EFFECTS: Concurrent use of etrasimod with immunosuppressive or immune-modulating agents may result in an increased risk of serious and fatal infections, such as disseminated herpetic infection, cryptococcal infection, or progressive multifocal leukoencephalopathy (PML).(1)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications increases the risk of adverse effects.
PATIENT MANAGEMENT: The etrasimod US prescribing information states etrasimod has not been studied in combination with anti-neoplastic, immune-modulating, or immunosuppressive therapies. Concomitant administration of these therapies with etrasimod should be avoided because of the risk of additive immune effects during therapy and in the weeks following administration. Etrasimod's effect on peripheral lymphocytes may persist for up to 5 weeks after discontinuation.(1) When switching from drugs with prolonged immune effects, the half-life and mode of action of these drugs must be considered in order to avoid unintended additive immunosuppressive effects.(1)
DISCUSSION: Fatal disseminated herpes zoster and herpes simplex infections, cryptococcal meningitis, disseminated cryptococcal infections, and cases of progressive multifocal leukoencephalopathy (PML) have been reported in patients treated with other sphingosine-1 phosphate receptor modulators.(1)
Immunosuppressives; Immunomodulators/Filgotinib
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Concurrent use of filgotinib with other immunosuppressants or immunomodulators including azathioprine, cyclosporine, tacrolimus, biologic disease-modifying antirheumatic drugs (DMARDs), or other Janus kinase (JAK) inhibitors may result in additive or synergistic effects on the immune system.(1)
CLINICAL EFFECTS: Concurrent use of filgotinib with other immunosuppressants or immunomodulators including azathioprine, cyclosporine, tacrolimus, biologic DMARDs, or other JAK inhibitors may increase the risk of serious infections.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The UK manufacturer of filgotinib states that concurrent use of filgotinib with other immunosuppressants or immunomodulators including azathioprine, cyclosporine, tacrolimus, biologic DMARDs, or other JAK inhibitors is not recommended.(1)
DISCUSSION: Serious infections have been reported in patients receiving filgotinib. Caution should be used in patients with a higher incidence of serious infection, including elderly patients aged 75 years and older.(1)
Immunosuppressives; Immunomodulators/Fingolimod
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Fingolimod in combination with immunosuppressives and immune-modulators all suppress the immune system.(1-3)
CLINICAL EFFECTS: Concurrent use of fingolimod with immunosuppressive or immune-modulating agents may result in an increased risk of serious infections, such as disseminated herpetic infection or progressive multifocal leukoencephalopathy (PML), an opportunistic infection caused by the JC virus (JCV).(1-3)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications.
PATIENT MANAGEMENT: Recommendations for fingolimod regarding this interaction differ between regulatory approving agencies. The fingolimod US prescribing information states: - Antineoplastic, immune-modulating, or immunosuppressive therapies, (including corticosteroids) are expected to increase the risk of immunosuppression, and the risk of additive immune system effects must be considered if these therapies are coadministered with fingolimod. When switching from drugs with prolonged immune effects, such as natalizumab, teriflunomide or mitoxantrone, the duration and mode of action of these drugs must be considered to avoid unintended additive immunosuppressive effects when initiating fingolimod.(1) The fingolimod Canadian prescribing information states: - Concurrent use with immunosuppressive or immunomodulatory agents is contraindicated due to the risk of additive immune system effects. However, co-administration of a short course of corticosteroids (up to 5 days) did not increase the overall rate of infection in patients participating Phase III clinical trials.(2) The fingolimod UK specific product characteristics states: - Fingolimod is contraindicated in patients currently receiving immunosuppressive therapies or those immunocompromised by prior therapies. When switching patients from another disease modifying therapy to Gilenya, the half-life and mode of action of the other therapy must be considered in order to avoid an additive immune effect whilst at the same time minimizing the risk of disease activation.(3)
DISCUSSION: Fatal disseminated herpes zoster and herpes simplex infections and cases of progressive multifocal leukoencephalopathy (PML) have been reported in patients who previously received immunomodulators or immunosuppressants.(1-3)
Immunosuppressives; Immunomodulators/Inebilizumab
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Inebilizumab, immunosuppressives, and immunomodulators all suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of inebilizumab with immunosuppressive or immunomodulating agents may result in myelosuppression including neutropenia resulting in an increased risk for serious infections.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of inebilizumab states that the concurrent use of inebilizumab with immunosuppressive agents, including systemic corticosteroids, may increase the risk of infection. If concurrent therapy is warranted, consider the risk of additive immune suppression and monitor based on prescribing information for both agents.(1)
DISCUSSION: Inebilizumab has not been studied in combination with other immunosuppressants. If concurrent therapy is warranted, consider the potential for increased immunosuppressive risks from both agents. The most common infections reported by inebilizumab treated patients in the randomized and open-label clinical trial periods included urinary tract infections (20%), nasopharyngitis (13%), upper respiratory tract infections (8%), and influenza (7%). Although there been no cases of Hepatitis B virus reactivation or progressive multifocal leukoencephalopathy reported in patients taking inebilizumab, these infections have been observed in patients taking other B-cell-depleting antibodies.(1)
Immunosuppressives; Immunomodulators/Ozanimod
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Ozanimod in combination with immunosuppressives and immune-modulators all suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of ozanimod with immunosuppressive or immune-modulating agents may result in an increased risk of serious infections, such as disseminated herpetic infection or progressive multifocal leukoencephalopathy (PML), an opportunistic infection caused by the JC virus (JCV).(1)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications.
PATIENT MANAGEMENT: The ozanimod US prescribing information state this information regarding this interaction: -Ozanimod has not been studied in combination with anti-neoplastic, immune-modulating, or immunosuppressive therapies. Caution should be used during concomitant administration because of the risk of additive immune effects during therapy and in the week following administration. When switching from drugs with prolonged immune effects, the half-life and mode of action of these drugs must be considered in order to avoid unintended additive immunosuppressive effects. Initiating treatment with ozanimod after alemtuzumab is not recommended. However, ozanimod can generally be started immediately after discontinuation of beta interferon or glatiramer acetate.(1)
DISCUSSION: Fatal disseminated herpes zoster and herpes simplex infections and cases of progressive multifocal leukoencephalopathy (PML) have been reported in patients who previously received immunomodulators or immunosuppressants.(1)
Immunosuppressives; Immunomodulators/Ponesimod
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Ponesimod in combination with immunosuppressives and immune-modulators all suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of ponesimod with immunosuppressive or immune-modulating agents may result in an increased risk of serious infections, such as disseminated herpetic infection, cryptococcal infection, or progressive multifocal leukoencephalopathy (PML), an opportunistic infection caused by the JC virus (JCV).(1)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications.
PATIENT MANAGEMENT: The ponesimod US prescribing information states ponesimod has not been studied in combination with anti-neoplastic, immune-modulating, or immunosuppressive therapies. Caution should be used during concomitant administration because of the risk of additive immune effects during therapy and in the weeks following administration. When switching from drugs with prolonged immune effects, the half-life and mode of action of these drugs must be considered in order to avoid unintended additive immunosuppressive effects. Initiating treatment with ponesimod after alemtuzumab is not recommended. However, ponesimod can generally be started immediately after discontinuation of beta interferon or glatiramer acetate.(1)
DISCUSSION: Fatal disseminated herpes zoster and herpes simplex infections, cryptococcal meningitis, disseminated cryptococcal infections, and cases of progressive multifocal leukoencephalopathy (PML) have been reported in patients who previously received immunomodulators or immunosuppressants.(1)
Immunosuppressives; Immunomodulators/Ritlecitinib
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Ritlecitinib, immunosuppressives, and immunomodulators all suppress the immune system.
CLINICAL EFFECTS: Concurrent use of ritlecitinib with immunosuppressives or immunomodulators may result in an increased risk of serious infections.
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of ritlecitinib states that concurrent use of ritlecitinib with other JAK inhibitors, biologic immunomodulators, cyclosporine or other potent immunosuppressants is not recommended.(1)
DISCUSSION: Serious infections have been reported in patients receiving ritlecitinib. Reported infections included appendicitis, COVID-19 infection (including pneumonia), and sepsis. Reports of viral reactivation, including herpes virus reactivation was reported in clinical studies with ritlecitinib.(1)
Immunosuppressives; Immunomodulators/Siponimod
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Siponimod in combination with immunosuppressives and immune-modulators all suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of siponimod with immunosuppressive or immune-modulating agents may result in an increased risk of serious infections, such as disseminated herpetic infection or progressive multifocal leukoencephalopathy (PML), an opportunistic infection caused by the JC virus (JCV).(1)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications.
PATIENT MANAGEMENT: The siponimod US prescribing information state this information regarding this interaction: -Siponimod has not been studied in combination with anti-neoplastic, immune-modulating, or immunosuppressive therapies. Caution should be used during concomitant administration because of the risk of additive immune effects during therapy and in the week following administration. When switching from drugs with prolonged immune effects, the half-life and mode of action of these drugs must be considered in order to avoid unintended additive immunosuppressive effects. Initiating treatment with siponimod after alemtuzumab is not recommended. However, siponimod can generally be started immediately after discontinuation of beta interferon or glatiramer acetate.(1)
DISCUSSION: Fatal disseminated herpes zoster and herpes simplex infections and cases of progressive multifocal leukoencephalopathy (PML) have been reported in patients who previously received immunomodulators or immunosuppressants.(1)
Immunosuppressives; Immunomodulators/Tofacitinib
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Concurrent use of tofacitinib and azathioprine, other biologic disease-modifying antirheumatic drugs (DMARDs), or potent immunosuppressants may result in additive or synergistic effects on the immune system.(1)
CLINICAL EFFECTS: Concurrent use of tofacitinib and azathioprine, other biologic DMARDs, or potent immunosuppressants use may increase the risk of serious infections.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: Tofacitinib should not be used concurrently with azathioprine, other biologic DMARDs, or cyclosporine.(1) Patient should be monitored for decreases in lymphocytes and neutrophils. Therapy should be adjusted based on the indication. - For all indications: If absolute neutrophil count (ANC) or lymphocyte count is less than 500 cells/mm3, discontinue tofacitinib. - For rheumatoid arthritis or psoriatic arthritis and absolute neutrophil count (ANC) 500 to 1000 cells/mm3: interrupt dosing. When ANC is greater than 1000 cells/mm3, resume Xeljanz 5 mg twice daily or Xeljanz XR 11 mg once daily. - For ulcerative colitis and ANC 500 to 1000 cells/mm3: -If taking Xeljanz 10 mg twice daily, decrease to 5 mg twice daily. When ANC is greater than 1000 cells/mm3, increase to 10 mg twice daily based on clinical response. -If taking Xeljanz 5 mg twice daily, interrupt dosing. When ANC is greater than 1000 cells/mm3, resume 5 mg twice daily. -If taking Xeljanz XR 22 mg once daily, decrease to 11 mg once daily. When ANC is greater than 1000 cells/mm3, increase to 22 mg once daily based on clinical response. -If taking Xeljanz XR 11 mg once daily, interrupt dosing. When ANC is greater than 1000 cells/mm3, resume 11 mg once daily. - For polyarticular course juvenile idiopathic arthritis (pcJIA) and ANC 500 to 1000 cells/mm3: interrupt dosing until ANC is greater than 1000 cells/mm3.(1)
DISCUSSION: Concurrent use of tofacitinib and azathioprine, other biologic DMARDs, or potent immunosuppressants may increase the risk of infection.(1) Serious infections due to bacterial, mycobacterial, invasive fungal, viral, or other opportunistic pathogens have been reported in patients receiving tofacitinib. Some patients presented with disseminated disease and were often taking concomitant immunomodulating agents. In the ulcerative colitis population, a greater risk of serious infections was seen with a higher tofacitinib dose. In 7 placebo-controlled rheumatoid arthritis trials (0-3 months exposure), the overall frequency of infections was 20% in the tofacitinib 5 mg twice daily group and 22% in the tofacitinib 10 mg twice daily group compared to 18% in the placebo group. Serious infections were reported in 11 patients (1.7 events per 100 patient-years) with a rate difference between treatment groups of 1.1 (-0.4, 2.5) events per 100 patient-years for both tofacitinib 5 mg twice daily and 10 mg twice daily. During 0-12 months exposure, serious infections were reported in 34 patients (2.7 events per 100 patient years) in the tofacitinib 5 mg twice daily group and 33 patients (2.7 events per 100 patient years) in the tofacitinib 10 mg twice daily group.(1)
Immunosuppressives; Immunomodulators/Upadacitinib
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Upadacitinib, immunosuppressives, and immunomodulators all suppress the immune system.
CLINICAL EFFECTS: Concurrent use of upadacitinib with immunosuppressives or immunomodulators may result in an increased risk of serious infections.
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of upadacitinib states that concurrent use of upadacitinib with immunosuppressives or immunomodulators is not recommended.
DISCUSSION: Serious infections have been reported in patients receiving upadacitinib. Reported infections included pneumonia, cellulitis, tuberculosis, multidermatomal herpes zoster, oral/esophageal candidiasis, cryptococcosis. Reports of viral reactivation, including herpes virus reactivation and hepatitis B reactivation, were reported in clinical studies with upadacitinib.(1)
Myelosuppressive Mod-Weak 3A4 Inh/Sirolimus Protein-Bound
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Moderate and weak immunosuppressive CYP3A4 inhibitors may inhibit the metabolism of sirolimus by CYP3A4 and increase the risk of additive immunosuppression.(1)
CLINICAL EFFECTS: Concurrent use of moderate or weak CYP3A4 inhibitors may result in elevated levels of and side effects from sirolimus including immunosuppression.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of sirolimus protein-bound injection (Fyarro) states a dose reduction to 56 mg/m2 is recommended when used concurrently with moderate or weak CYP3A4 inhibitors. Concurrent use with strong CYP3A4 inhibitors should be avoided.(1) For patients on avapritinib: this interaction applies only to gastrointestinal stromal tumor (GIST) patients on avapritinib 200 mg or 300 mg.(2)
DISCUSSION: In an open, randomized, cross-over trial in 18 healthy subjects, concurrent single doses of diltiazem (120 mg) and sirolimus (10 mg) increased sirolimus area-under-curve (AUC) and maximum concentration (Cmax) by 60% and by 43%, respectively. Sirolimus apparent oral clearance and volume of distribution decreased by 38% and 45%, respectively. There were no effects on diltiazem pharmacokinetics or pharmacodynamics.(3) In a study in 26 healthy subjects, concurrent sirolimus (2 mg daily) with verapamil (180 mg twice daily) increased sirolimus AUC and Cmax by 2.2-fold and 2.3-fold, respectively. The AUC and Cmax of the active S-enantiomer of verapamil each increased by 1.5-fold. Verapamil time to Cmax (Tmax) was increased by 1.2 hours.(3) Moderate CYP3A4 inhibitors linked to this monograph include: duvelisib, fedratinib, imatinib, rilzabrutinib, and treosulfan.(3,4) Weak CYP3A4 inhibitors linked to this monograph include: asciminib, avapritinib, belumosudil, capivasertib, everolimus, lapatinib, larotrectinib, leflunomide, olaparib, palbociclib, teriflunomide, vepdegestrant, and ziftomenib.(4,5)
Myelosuppressives; Immunomodulators/Sodium Iodide I 131
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Sodium iodide I 131 can cause depression of the hematopoetic system. Myelosuppressives and immunomodulators also suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of sodium iodide I 131 with agents that cause bone marrow depression, including myelosuppressives or immunomodulators, may result in an enhanced risk of hematologic disorders, including anemia, blood dyscrasias, bone marrow depression, leukopenia, and thrombocytopenia. Bone marrow depression may increase the risk of serious infections and bleeding.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of sodium iodide I 131 states that concurrent use with bone marrow depressants may enhance the depression of the hematopoetic system caused by large doses of sodium iodide I 131.(1) Sodium iodide I 131 causes a dose-dependent bone marrow suppression, including neutropenia or thrombocytopenia, in the 3 to 5 weeks following administration. Patients may be at increased risk of infections or bleeding during this time. Monitor complete blood counts within one month of therapy. If results indicate leukopenia or thrombocytopenia, dosimetry should be used to determine a safe sodium iodide I 131 activity.(1)
DISCUSSION: Hematologic disorders including death have been reported with sodium iodide I 131. The most common hematologic disorders reported include anemia, blood dyscrasias, bone marrow depression, leukopenia, and thrombocytopenia.(1)
Palbociclib/Atorvastatin; Lovastatin; Simvastatin
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Palbociclib is a weak CYP3A4 inhibitor.(1) Atorvastatin, lovastatin, and simvastatin are sensitive CYP3A4 substrates.(2) Palbociclib may inhibit the metabolism of atorvastatin, lovastatin, and simvastatin.
CLINICAL EFFECTS: Concurrent palbociclib may result in increased levels of atorvastatin, lovastatin, or simvastatin, which may result in hepatic injury, myopathy or rhabdomyolysis. Symptoms of rhabdomyolysis include muscle pain, tenderness, weakness, elevated creatine kinase levels, and reddish-brown, heme positive urine.
PREDISPOSING FACTORS: The risk for myopathy or rhabdomyolysis may be greater in patients 65 years and older, inadequately treated hypothyroidism, renal impairment, carnitine deficiency, malignant hyperthermia, or in patients with a history of myopathy or rhabdomyolysis. Patients with a SLCO1B1 polymorphism that leads to decreased function of the hepatic uptake transporter OATP1B1 may have increased statin concentrations and be predisposed to myopathy or rhabdomyolysis.
PATIENT MANAGEMENT: The manufacturer of palbociclib states that drug levels of sensitive CYP3A4 substrates like atorvastatin, lovastatin, and simvastatin may be elevated by palbociclib and to consider dose reduction of the CYP3A4 substrate.(1) The UK manufacturer of simvastatin states that concomitant administration of simvastatin and palbociclib is not recommended.(7) Consider the risks versus benefits of continuing antilipidemic therapy. Monitor patients receiving concurrent therapy for signs of rhabdomyolysis.
DISCUSSION: A study in 26 healthy women found that palbociclib at steady state increased the maximum concentration (Cmax) and area-under-curve (AUC) of concomitant midazolam (a CYP3A4 substrate) by 37 % and 61 %, respectively, compared to midazolam alone.(3) A case report described a potential interaction in which palbociclib (125 mg daily) was initiated in a patient with metastatic breast cancer who had been taking atorvastatin (40 mg daily) for years. After two cycles of palbociclib, the patient developed rapidly progressive muscle pain and weakness, elevated creatinine kinase of 14,572 units/L, and died after 8 days of hospitalization.(4) A case of transaminitis and rhabdomyolysis was reported during a phase 2 trial of palbociclib in a patient on concomitant simvastatin (80 mg daily). The symptoms improved upon discontinuation of palbociclib.(4,5) A case report described a potential interaction in which palbociclib (125 mg) was initiated in a patient with metastatic breast cancer who had been taking simvastatin for over 20 years (currently on simvastatin 20mg/ezetimibe 10mg). After 20 days of palbociclib, the patient developed proximal tetraparesis and intense rhabdomyolysis with elevated creatinine kinase of 18,000 units/L.(8) A case report described a potential interaction in which palbociclib (125 mg daily for 21 days) was initiated in a metastatic breast cancer patient who had been taking simvastatin (40 mg) for years. After one cycle of palbociclib, the patient developed tetraparesis and near fatal rhabdomyolysis (creatinine kinase 22,000 units/L).(9) In a case report, a metastatic breast cancer patient on palbociclib (125 mg) and simvastatin (40 mg) presented with rapid progression of muscle weakness, difficulty standing, fatigue, and elevated creatinine kinase (9024 units/L).(10) In a PKPB model, concurrent use of atorvastatin (40 mg daily) with palbociclib (125 mg daily for 2 months) increased the simulated Cmax and AUC of atorvastatin by 1.16-fold and 1.36-fold, respectively, and increased the simulated Cmax and AUC of atorvastatin lactone by 1.58-fold and 1.73-fold, respectively.(6)
Palbociclib/Strong Cyp3a4 Inhibitors
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Agents that inhibit the CYP3A4 isoenzyme may inhibit the metabolism of palbociclib.(1)
CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inhibitors may increase levels of and effects from palbociclib, including neutropenia, interstitial lung disease, or pneumonitis.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: Avoid the use of strong CYP3A4 inhibitors in patients undergoing therapy with palbociclib.(1) Consider alternatives with no or minimal enzyme inhibition. If concurrent use with palbociclib cannot be avoided, reduce the dose of palbociclib to 75 mg daily. If the 3A4 inhibitor is discontinued, a washout period of 3-5 half-lives of the inhibitor should occur before the palbociclib dose is adjusted upward.(1)
DISCUSSION: In a study in 12 healthy subjects, itraconazole (200 mg daily) increased the concentration maximum (Cmax) and area-under-curve (AUC) of a single dose of palbociclib by 34% and 87%, respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, ensitrelvir, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, lonafarnib, lopinavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, relacorilant, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, or voriconazole.(2,3)
Selected Immunosuppressants/Leflunomide; Teriflunomide
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Concurrent use of leflunomide or teriflunomide and potent immunosuppressants may result in additive or synergistic effects on the immune system.(1,2) Leflunomide is a prodrug and is converted to its active metabolite teriflunomide.(1)
CLINICAL EFFECTS: Concurrent use of leflunomide or teriflunomide with immunosuppressants may result in an increased risk of serious infections, including opportunistic infections, especially Pneumocystis jiroveci pneumonia, tuberculosis (including extra-pulmonary tuberculosis), and aspergillosis.
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: If leflunomide or teriflunomide is used concurrently with immunosuppressive agents, chronic CBC monitoring should be performed more frequently, every month instead of every 6 to 8 weeks. If bone marrow suppression or a serious infection occurs, leflunomide or teriflunomide should be stopped and rapid drug elimination procedure should be performed.(1,2)
DISCUSSION: Pancytopenia, agranulocytosis and thrombocytopenia have been reported in patients receiving leflunomide or teriflunomide alone, but most frequently in patients taking concurrent immunosuppressants.(1,2) Severe and potentially fatal infections, including sepsis, have been reported in patients receiving leflunomide or teriflunomide, especially Pneumocystis jiroveci pneumonia and aspergillosis. Tuberculosis has also been reported.(1,2)
Selected Myelosuppressive Agents/Clozapine
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Clozapine and other myelosuppressive agents may be associated with neutropenia or agranulocytosis.(2)
CLINICAL EFFECTS: Moderate neutropenia, even if due to combination therapy, may require abrupt discontinuation of clozapine resulting in decompensation of the patient's psychiatric disorder (e.g. schizophrenia). The disease treated by the myelosuppressive agent may be compromised if myelosuppression requires dose reduction, delay, or discontinuation of the myelosuppressive agent. Undetected severe neutropenia or agranulocytosis may be fatal.
PREDISPOSING FACTORS: Low white blood counts prior to initiation of the myelosuppressive agent may increase risk for clinically significant neutropenia.
PATIENT MANAGEMENT: If a patient stabilized on clozapine therapy requires treatment with a myelosuppressive agent, the clozapine prescriber should consult with prescriber of the myelosuppressive agent (e.g. oncologist) to discuss treatment and monitoring options.(2) More frequent absolute neutrophil count (ANC) monitoring or treatment alternatives secondary to neutropenic episodes may need to be considered. The U.S. Food and Drug Administration (FDA) recommends that prescribers monitor patients' ANC according to the monitoring frequencies described in the prescribing information. Severe neutropenia remains a serious, potentially fatal risk that is greatest in the first several months of clozapine treatment. ANC monitoring can help identify neutropenia early to allow for timely intervention.(1-2) Australia, Canada, and U.K.: Clozapine is only available through a restricted distribution system which requires documentation of the ANC prior to dispensing. For most clozapine patients, clozapine treatment must be interrupted for a suspected clozapine-induced ANC < 1000 cells/microliter. For patients with benign ethnic neutropenia (BEN), treatment must be interrupted for suspected clozapine-induced neutropenia < 500 cells/microliter.(2)
DISCUSSION: Concurrent use of clozapine and selected myelosuppressive agents may require more frequent ANC monitoring or consideration of treatment alternatives secondary to neutropenic episodes. Agents linked to this interaction generally have > 5% risk for neutropenia and/or warnings describing risk for myelosuppression in manufacturer prescribing information.(3-26)
Selected Myelosuppressive Agents/Deferiprone
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Concurrent use of deferiprone with other drugs known to be associated with neutropenia or agranulocytosis may increase the frequency or risk for severe toxicity.(1)
CLINICAL EFFECTS: Concurrent use of deferiprone and myelosuppressive agents may result in severe neutropenia or agranulocytosis, which may be fatal.
PREDISPOSING FACTORS: Agranulocytosis may be less common in patients receiving deferiprone for thalassemia, and more common in patients treated for other systemic iron overload conditions (e.g. myelodysplastic syndromes, sickle cell disease).(2,3) Inadequate monitoring appears to increase the risk for severe outcomes. Manufacturer post market surveillance found that in all fatal cases of agranulocytosis reported between 1999 and 2005, data on weekly white blood count (WBC) monitoring was missing. In three fatal cases, deferiprone was continued for two to seven days after the detection of neutropenia or agranulocytosis.(2)
PATIENT MANAGEMENT: If possible, discontinue one of the drugs associated with risk for neutropenia or agranulocytosis. If alternative therapy is not available, documentation and adherence to the deferiprone monitoring protocol is essential. Baseline absolute neutrophil count (ANC) must be at least 1,500/uL prior to starting deferiprone. Monitor ANC weekly during therapy. If infection develops, interrupt deferiprone therapy and monitor ANC more frequently. If ANC is less than 1,500/uL but greater than 500/uL, discontinue deferiprone and any other drugs possibly associated with neutropenia. Initiate ANC and platelet counts daily until recovery (i.e. ANC at least 1,500/uL). If ANC is less than 500/uL, discontinue deferiprone, evaluate patient and hospitalize if appropriate. Do not resume deferiprone unless potential benefits outweigh potential risks.(1)
DISCUSSION: Drugs linked to this monograph have an FDA Boxed Warning for risk of neutropenia, agranulocytosis, or pancytopenia, or have > 5% risk for neutropenia and/or warnings describing risk for myelosuppression in manufacturer prescribing information.(1-25) In pooled clinical studies submitted to the FDA, 6.1% of deferiprone patients met criteria for neutropenia and 1.7% of patients developed agranulocytosis.(1) The time to onset of agranulocytosis was highly variable with a range of 65 days to 9.2 years (median, 161 days).(3)
Selected Myelosuppressive Agents/Dipyrone
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Concurrent use of dipyrone with other drugs known to be associated with neutropenia or agranulocytosis may increase the frequency or risk for severe toxicity.(1-29)
CLINICAL EFFECTS: Concurrent use of dipyrone with agents that cause bone marrow depression, including myelosuppressives, may result in an enhanced risk of hematologic disorders, including anemia, blood dyscrasias, bone marrow depression, leukopenia, and thrombocytopenia. Bone marrow depression may increase the risk of serious infections and bleeding. Undetected severe neutropenia or agranulocytosis may be fatal.(1-29)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: Concurrent use of dipyrone and myelosuppressive agents should be avoided. The European Medicines Agency states dipyrone is contraindicated in patients with a prior medical history of dipyrone-induced agranulocytosis (or from other pyrazolones/pyrazolidines), impaired bone marrow function or diseases of the hematopoietic system.(3) International labeling for dipyrone and methotrexate state that co-administration may increase the hematotoxicity of methotrexate, especially in elderly patients, and therefore should be avoided.(1-2) The European Medicines Agency advises if agranulocytosis is suspected with dipyrone, a complete blood count (including differential blood count) should be performed immediately, and treatment must be stopped while waiting for the results. If confirmed, treatment must not be reintroduced.(1-3)
DISCUSSION: A retrospective cohort study analyzed new users of dipyrone (n=444,972), non-steroidal anti-inflammatory drugs (n=3,814,367) which served as a reference cohort, and opioids-paracetamol (n=3,129,221) which was the negative control. During continuous treatment over a median of 37-40 days, 26 cases of hospitalized agranulocytosis occurred. With the assumption that agranulocytosis onset was 7 days prior to admission, the hazard ratio of agranulocytosis associated with dipyrone was 4.40 [0.90-21.57] compared to NSAIDs and 2.45 [0.68-8.83] compared to opioid-paracetamol. HR of neutropenia from dipyrone was 2.98 [1.57-5.65] compared to NSAIDs and not statistically significant compared to opioids-paracetamol. In a sensitivity analysis assuming that the onset of agranulocytosis was the date of hospitalization, the HR of dipyrone-induced agranulocytosis was 7.20 [95% confidence interval: 1.92-26.99] compared to NSAIDs and 3.31 [1.17-9.34] compared to opioids-paracetamol. Agranulocytosis was very rare but more than 4 times more common with dipyrone than other analgesics.(4) In a review of 1,448 reports of agranulocytosis attributed to dipyrone, patients with fatal outcomes were older and more often had also received methotrexate compared to those with non-fatal outcomes (odds ratio: 5.18; 95% confidence interval: 3.06-8.78).(5) Agents linked to this interaction generally have > 5% risk for neutropenia and/or warnings describing risk for myelosuppression in manufacturer prescribing information.(2,6-26)
Slt Immunosuppress; Immunomodulator/Ropeginterferon Alfa-2B
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Ropeginterferon alfa-2b and immunosuppressives both suppress the immune system.
CLINICAL EFFECTS: Concurrent use of ropeginterferon alfa-2b with immunosuppressives may result in an increased risk of serious infections.
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: Avoid concurrent use of myelosuppressive agents.(1-2) If concurrent use cannot be avoided, monitor for effects of excessive immunosuppression.
DISCUSSION: In clinical trials, 20% of patients experienced leukopenia. Interferon alfa products may cause fatal or life-threatening infections.(1-2)
Weak Cyp3a4 Inhibitors/Eliglustat
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Weak inhibitors of CYP3A4 may inhibit the metabolism of eliglustat. If the patient is also taking an inhibitor of CYP2D6, eliglustat metabolism can be further inhibited.(1)
CLINICAL EFFECTS: Concurrent use of an agent that is a weak inhibitor of CYP3A4 may result in elevated levels of and clinical effects of eliglustat, including prolongation of the PR, QTc, and/or QRS intervals, which may result in life-threatening cardiac arrhythmias.(1)
PREDISPOSING FACTORS: If the patient is also taking an inhibitor of CYP2D6, is a poor metabolizer of CYP2D6, and/or has hepatic impairment, eliglustat metabolism can be further inhibited.(1) The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2)
PATIENT MANAGEMENT: The concurrent use of eliglustat with weak inhibitors of CYP3A4 in poor metabolizers of CYP2D6 should be avoided.(1) The dosage of eliglustat with weak inhibitors of CYP3A4 in extensive metabolizers of CYP2D6 with mild (Child-Pugh Class A) hepatic impairment should be limited to 84 mg daily.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. For patients on avapritinib: this interaction applies only to gastrointestinal stromal tumor (GIST) patients on avapritinib 200 mg or 300 mg.(3)
DISCUSSION: Ketoconazole (400 mg daily), a strong inhibitor of CYP3A4, increased eliglustat (84 mg BID) maximum concentration (Cmax) and area-under-curve (AUC) by 4-fold and 4.4-fold, respectively, in extensive metabolizers. Physiologically-based pharmacokinetic (PKPB) models suggested ketoconazole would increase eliglustat Cmax and AUC by 4.4-fold and 5.4-fold, respectively, in intermediate metabolizers. PKPB models suggested ketoconazole may increase the Cmax and AUC of eliglustat (84 mg daily) by 4.3-fold and 6.2-fold, respectively, in poor metabolizers.(1) PKPB models suggested fluconazole, a moderate inhibitor of CYP3A4, would increase eliglustat Cmax and AUC by 2.8-fold and 3.2-fold, respectively, in extensive metabolizers and by 2.5-fold and 2.9-fold, respectively in intermediate metabolizers. PKPB models suggest that concurrent eliglustat (84 mg BID), paroxetine (a strong inhibitor of CYP2D6), and ketoconazole would increase eliglustat Cmax and AUC by 16.7-fold and 24.2-fold, respectively, in extensive metabolizers. In intermediate metabolizers, eliglustat Cmax and AUC would be expected to increase 7.5-fold and 9.8-fold, respectively.(1) PKPB models suggest that concurrent eliglustat (84 mg BID), terbinafine (a moderate inhibitor of CYP2D6), and ketoconazole would increase eliglustat Cmax and AUC by 10.2-fold and 13.6-fold, respectively, in extensive metabolizers. In intermediate metabolizers, eliglustat Cmax and AUC would be expected to increase 4.2-fold and 5-fold, respectively.(1) Weak inhibitors of CYP3A4 include: amlodipine, anamorelin, asciminib, avapritinib, azithromycin, Baikal skullcap, belumosudil, berberine, bicalutamide, blueberry, brodalumab, camizestrant, cannabidiol, chlorzoxazone, cilostazol, cimetidine, ciprofloxacin, clotrimazole, cranberry, cyclosporine, daclatasvir, daridorexant, delavirdine, dihydroberberine, diosmin, elinzanetant, everolimus, flibanserin, fosaprepitant, fostamatinib, gepotidacin, ginkgo, givinostat, glecaprevir/pibrentasvir, goldenseal, grazoprevir, isoniazid, istradefylline, ivacaftor, lacidipine, lapatinib, larotrectinib, lazertinib, leflunomide, levamlodipine, linagliptin, lomitapide, lurasidone, olaparib, osilodrostat, palbociclib, pazopanib, peppermint oil, piperine, propiverine, propofol, ranolazine, resveratrol, roxithromycin, rucaparib, selpercatinib, simeprevir, sitaxsentan, skullcap, teriflunomide, ticagrelor, tolvaptan, trofinetide, vepdegestrant, vonoprazan, and ziftomenib.(4,5)
Weak Cyp3a4 Inhibitors/Lomitapide
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Weak inhibitors of CYP3A4 may inhibit the metabolism of lomitapide.(1) Lomitapide is very susceptible to CYP3A4 inhibition. For example, in an interaction study with a strong CYP3A4 inhibitor (ketoconazole) lomitapide exposure was increased 27-fold.(2) Thus even weak CYP3A4 inhibitors may affect lomitapide exposure (AUC, area-under-curve).
CLINICAL EFFECTS: Concurrent use of a weak inhibitor of CYP3A4 may result in 2-fold increases in lomitapide levels and toxicity from lomitapide.(1)
PREDISPOSING FACTORS: This interaction may be more severe in patients with hepatic impairment or with end-stage renal disease.(1)
PATIENT MANAGEMENT: When initiating lomitapide in patients taking a stable dose of a weak CYP3A4 inhibitor, follow the recommended dose and titration schedule per labeling. When initiating a weak CYP3A4 inhibitor in patients taking lomitapide, decrease the dose of lomitapide by 50%. The maximum recommended lomitapide dose with concurrent weak CYP3A4 inhibitors should be: -Adults (age 18 years and older): 30 mg daily, -Age group 11 to 17 years: 20 mg daily, -Age group 2 to 10 years: 10 mg daily. Due to lomitapide's long half-life, it may take 1 to 2 weeks to see the full effect of this interaction.(1) For patients on avapritinib: this interaction applies only to gastrointestinal stromal tumor (GIST) patients on avapritinib 200 mg or 300 mg.(2)
DISCUSSION: Lomitapide is very susceptible to CYP3A4 inhibition. For example, in an interaction study with a strong CYP3A4 inhibitor (ketoconazole) lomitapide exposure was increased 27-fold.(2) Based upon interactions with stronger inhibitors, weak inhibitors of CYP3A4 are predicted to increase lomitapide area-under-curve(AUC) 2-fold.(1) Weak CYP3A4 inhibitors linked to this interaction include: amiodarone, amlodipine, anamorelin, asciminib, atorvastatin, avapritinib, azithromycin, Baikal skullcap, belumosudil, bicalutamide, blueberry juice, brodalumab, camizestrant, cannabidiol, capivasertib, cilostazol, cimetidine, ciprofloxacin, chlorzoxazone, clotrimazole, cranberry juice, cyclosporine, daridorexant, delavirdine, diosmin, elinzanetant, everolimus, flibanserin, fosaprepitant, fostamatinib, gepotidacin, ginkgo, givinostat, glecaprevir/pibrentasvir, goldenseal, grazoprevir, isoniazid, istradefylline, ivacaftor, lacidipine, lapatinib, larotrectinib, lazertinib, leflunomide, levamlodipine, linagliptin, lurasidone, maribavir, mavorixafor, olaparib, osilodrostat, palbociclib, pazopanib, peppermint oil, piperine, propiverine, propofol, ranitidine, ranolazine, resveratrol, roxithromycin, rucaparib, selpercatinib, sevabertinib, sitaxsentan, skullcap, teriflunomide, ticagrelor, tolvaptan, trofinetide, vepdegestrant, viloxazine, vonoprazan, ziftomenib, and zileuton.(1-3)
Weak Cyp3a4 Inhibitors/Pimozide
SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.
MECHANISM OF ACTION: Weak inhibitors of CYP3A4 may inhibit the metabolism of pimozide.(1,2)
CLINICAL EFFECTS: Concurrent use with weak CYP3A4 inhibitors may increase the levels and effects of pimozide including QTc prolongation and potentially life-threatening cardiac arrhythmias like torsades de pointes.(1-2) Concurrent use may also result in extrapyramidal symptoms such as akathisia, bradykinesia, cogwheel rigidity, dystonia, hypertonia, and oculogyric crisis.(1)
PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increased systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) The risk of anticholinergic toxicities including cognitive decline, delirium, falls and fractures is increased in geriatric patients using more than one medicine with anticholinergic properties.(4)
PATIENT MANAGEMENT: The US manufacturer of pimozide states that concomitant treatment with strong CYP3A4 inhibitors is contraindicated and treatment with less potent inhibitors of CYP3A4 should also be avoided.(1) The UK manufacturer of pimozide contraindicates concomitant use of pimozide with CYP3A4 inhibitors and CYP2D6 inhibitors, stating that inhibition of either or both CYP3A4 and CYP2D6 may result in the elevation of pimozide blood concentration and increase the possibility of QT-prolongation.(2) For patients on avapritinib: this interaction applies only to gastrointestinal stromal tumor (GIST) patients on avapritinib 200 mg or 300 mg.(5) If concurrent use cannot be avoided, then correct or minimize QT prolonging risk factors, use the lowest effective dose of pimozide, and discontinue other concurrent QT prolonging agents or CYP3A4 or CYP2D6 inhibitors if possible. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting.
DISCUSSION: Pimozide is metabolized at CYP3A.(1,5) Elevated levels of pimozide may prolong the QTc interval resulting in life-threatening ventricular arrhythmias.(1) Serious cardiovascular events, including QT prolongation, torsades de pointes, ventricular tachycardia, cardiac arrest, and/or sudden death have been reported in patients taking pimozide in combination with itraconazole and/or other CYP3A4 inhibitors.(1,2) Weak CYP3A4 inhibitors include: amlodipine, asciminib, avapritinib, belumosudil, berberine, bicalutamide, blueberry, brodalumab, camizestrant, cannabidiol, capivasertib, chlorzoxazone, cimetidine, clotrimazole, cranberry, cyclosporine, daclatasvir, daridorexant, dihydroberberine, diosmin, elinzanetant, everolimus, flibanserin, fostamatinib, ginkgo, glecaprevir/pibrentasvir, goldenseal, grazoprevir, isoniazid, istradefylline, ivacaftor, lacidipine, larotrectinib, lazertinib, leflunomide, levamlodipine, linagliptin, lomitapide, lurasidone, marijuana, olaparib, palbociclib, peppermint, piperine, pirtobrutinib, propiverine, ranitidine, resveratrol, scutellarin, sevabertinib, simeprevir, sitaxsentan, teriflunomide, ticagrelor, tolvaptan, trofinetide, viloxazine, and vonoprazan.(7,8)
Moderate Interaction: Assess the risk to the patient and take action as needed.
Immunosuppressives; Immunomodulators/Cladribine Oncology Inj
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: Cladribine in combination with immunosuppressives and immune-modulators all suppress the immune system.(1-4)
CLINICAL EFFECTS: Concurrent use of cladribine with immunosuppressive or immune-modulating agents may result in an increased risk of serious infections.(1-4)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications.
PATIENT MANAGEMENT: Recommendations for cladribine regarding this interaction differ between regulatory approving agencies. The cladribine US, UK, and Australian prescribing information state: -Caution should be exercised if cladribine injection is administered before, after, or in conjunction with other drugs known to cause immunosuppression or myelosuppression.(1-3) The cladribine Canadian prescribing information states: -Proceed carefully in patients with severe bone marrow impairment of any etiology since further suppression of bone marrow function should be anticipated.(4)
DISCUSSION: Severe bone marrow suppression, including neutropenia, anemia and thrombocytopenia, has been commonly observed in patients treated with cladribine injection, especially at high doses.(1-4)
Immunosuppressives; Immunomodulators/Covid-19 Vaccines
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: Immunosuppressants and immunomodulators may prevent the immune system from properly responding to the COVID-19 vaccine.(1-3)
CLINICAL EFFECTS: Administration of a COVID-19 vaccine with immunosuppressants or immunomodulators may interfere with vaccine-induced immune response and impair the efficacy of the vaccine. However, patients should be offered and given a COVID-19 vaccine even if the use and timing of immunosuppressive agents cannot be adjusted.(1-3)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The Centers for Disease Control and Prevention (CDC),(1) Infectious Diseases Society of America (IDSA),(2) and the American College of Rheumatology (ACR)(3) have published guidances for COVID-19 vaccination in patients on immunosuppressants. The CDC states that all immunocompromised patients over 6 months of age should receive at least 1 dose of COVID-19 vaccine if eligible. See the CDC's Interim Clinical Considerations for Use of COVID-19 Vaccines for specific recommendations based on age, vaccination history, and vaccine manufacturer.(1) The CDC advises planning for vaccination at least 2 weeks before starting or resuming immunosuppressive therapy.(1) IDSA recommends timing COVID-19 vaccination at least 2 weeks before starting or at least 3 months after completing immunosuppressive therapy.(2) The ACR states that in general, immunosuppressants and immunomodulators should be held for 1-2 weeks after each vaccine dose.(3) Patients should be offered and given a COVID-19 vaccine even if the use and timing of immunosuppressive agents cannot be adjusted, though the immune response will likely be blunted. COVID-19 vaccines should not be delayed in patients taking immunosuppressive therapies.(1-2) See below for specific recommendations for certain agents. B-cell depleting agents, including rituximab: The CDC states that the utility of B-cell quantification to guide clinical care is not known and is not recommended. Patients who receive B-cell depleting therapy on a continuing basis should receive COVID-19 vaccines about 4 weeks before the next scheduled dose. For patients who received 1 or more doses of COVID-19 vaccine during treatment with B-cell-depleting therapies that were administered over a limited period (e.g., as part of a treatment regimen for certain malignancies), revaccination may be considered according to the current CDC recommendations for unvaccinated patients. The suggested interval to start revaccination is about 6 months after completion of the B-cell-depleting therapy.(1) IDSA recommends waiting for at least 3-6 months after the last infusion of B-cell depleting therapy before administering COVID-19 vaccines.(2) The ACR recommends consulting with the rheumatologist to determine optimal timing of COVID-19 vaccination. Measuring CD19 B cells may be considered to determine need for a booster vaccine dose. If B cell levels are not measured, a supplemental vaccine dose 2-4 weeks before the next scheduled dose of rituximab is recommended.(3) Recipients of hematopoietic cell transplant or CAR-T-cell therapy who received one or more doses of COVID-19 vaccine prior to or during treatment should undergo revaccination following the current CDC recommendations for unvaccinated patients. Revaccination should start at least 3 months (12 weeks) after transplant or CAR-T-cell therapy.(1,2) The CDC includes abatacept, cyclophosphamide, and TNF-alpha and cytokine inhibitors in their general recommendation to hold therapy for at least 2 weeks following vaccination (1) while the ACR provides different recommendations:(3) *Abatacept: - Subcutaneous abatacept should be withheld for 1-2 weeks after each vaccine dose, as disease activity allows. - For intravenous abatacept, time administration so that vaccination will occur 1 week before the next abatacept infusion. *Cyclophosphamide: When feasible, administer cyclophosphamide 1 week after each COVID-19 vaccine dose. *TNF-alpha inhibitors and cytokine inhibitors: The ACR was not able to reach consensus on whether to modify dosing or timing of these agents with COVID-19 vaccination.
DISCUSSION: IDSA recommendations are based on cohort and case control studies in immunocompromised patients that found low to modest vaccine effectiveness (37-61%) but lower risks of COVID-19 association hospitalization, COVID-19 related mortality, and critical illness.(2) The ACR convened a COVID-19 Vaccine Guidance Task Force to provide guidance on optimal use of COVID-19 vaccines in rheumatology patients. These recommendations are based on limited clinical evidence of COVID-19 vaccines in patients without rheumatic and musculoskeletal disorders and evidence of other vaccines in this patient population.(3) The ACR recommendation for rituximab is based on studies of humoral immunity following receipt of other vaccines. These studies have uncertain generalizability to vaccination against COVID-19, as it is unknown if efficacy is attributable to induction of host T cells versus B cell (antibody-based) immunity.(3) The ACR recommendation for mycophenolate is based on preexisting data of mycophenolate on non-COVID-19 vaccine immunogenicity. Emerging data suggests that mycophenolate may impair SARS-CoV-2 vaccine response in rheumatic and musculoskeletal disease and transplant patients.(3) The ACR recommendation for methotrexate is based on data from influenza vaccines and pneumococcal vaccines with methotrexate.(3) The ACR recommendation for JAK inhibitors is based on concerns related to the effects of JAK inhibitors on interferon signaling that may result in a diminished vaccine response.(3) The ACR recommendation for subcutaneous abatacept is based on several studies suggesting a negative effect of abatacept on vaccine immunogenicity. The first vaccine dose primes naive T cells, naive T cell priming is inhibited by CTLA-4, and abatacept is a CTLA-4Ig construct. CTLA-4 should not inhibit boosts of already primed T cells at the time of the second vaccine dose.(3)
Immunosuppressives; Immunomodulators/Sarilumab
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: Sarilumab, immunosuppressives, and immunomodulators all suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of sarilumab with immunosuppressive or immunomodulating agents may result in an increased risk for serious infections.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of sarilumab recommends caution because the concurrent use of sarilumab with immunosuppressive agents may increase the risk of infection. If concurrent therapy is warranted, consider the risk of additive immune suppression and monitor based on prescribing information for both agents.(1)
DISCUSSION: Sarilumab was studied as monotherapy and in combination with methotrexate or conventional disease modifying antirheumatic drugs (DMARDs) in rheumatoid arthritis studies. Sarilumab has not been studied with biological DMARDs and concurrent use should be avoided. If concurrent therapy is warranted, consider the potential for increased immunosuppressive risks from both agents.(1) The most common infections reported by sarilumab treated patients in the clinical trial periods included pneumonia and cellulitis. Serious bacterial, mycobacterial, fungal, and viral infections were observed in patients receiving sarilumab. Cases of tuberculosis, candidiasis, and pneumocystis with sarilumab have been reported.(1)
Immunosuppressives; Immunomodulators/Tocilizumab
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: Tocilizumab, immunosuppressives, and immunomodulators all suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of tocilizumab with immunosuppressive or immunomodulating agents may result in an increased risk for serious infections.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of tocilizumab recommends caution because the concurrent use of tocilizumab with immunosuppressive agents may increase the risk of infection. If concurrent therapy is warranted, consider the risk of additive immune suppression and monitor based on prescribing information for both agents.(1)
DISCUSSION: Tocilizumab was studied as monotherapy and in combination with methotrexate, non-biologic DMARDs or corticosteroids, depending on the indication. Tocilizumab has not been studied with biological DMARDs and concurrent use should be avoided. If concurrent therapy is warranted, consider the potential for increased immunosuppressive risks from both agents.(1) The most common infections reported by tocilizumab treated patients in the clinical trial periods included pneumonia, urinary tract infection, cellulitis, herpes zoster, gastroenteritis, diverticulitis, sepsis and bacterial arthritis. Serious bacterial, mycobacterial, fungal, and viral infections were observed in patients receiving tocilizumab. Cases of tuberculosis, cryptococcus, aspergillosis, candidiasis, and pneumocystosis have been reported.(1)
Immunosuppressives; Immunomodulators/Ublituximab
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: Ublituximab, immunosuppressives, and immunomodulators all suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of ublituximab with immunosuppressive or immunomodulating agents may result in an increased risk for serious infections.(1)
PREDISPOSING FACTORS: Incomplete washout of previously prescribed immunosuppressive or immune-modulating medications.
PATIENT MANAGEMENT: The US manufacturer of ublituximab recommends caution because the concurrent use of ublituximab with immunomodulating or immunosuppressive agents, including immunosuppressant doses of corticosteroids, may increase the risk of infection.(1) If concurrent therapy is warranted, consider the risk of additive immune suppression and monitor based on prescribing information for both agents. When switching from agents with immune effects, the half-life and mechanism of action of these drugs must be taken into consideration in order to prevent additive immunosuppressive effects.(1)
DISCUSSION: The most common infections reported by ublituximab-treated patients in the clinical trial periods included upper respiratory tract infections and urinary tract infections. Serious, including life-threatening or fatal, bacterial and viral infections were observed in patients receiving ublituximab.(1) Serious and/or fatal bacterial, fungal, and new or reactivated viral infections have been associated with other anti-CD20 B-cell depleting therapies. There were no cases of progressive multifocal leukoencephalopathy (PML) reported during the clinical trials; however, there have been reports of PML during or following completion of other anti-CD20 B-cell depleting therapies.(1)
Immunosuppressives; Immunomodulators/Ustekinumab
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: Ustekinumab, immunosuppressives, and immunomodulators all suppress the immune system.(1)
CLINICAL EFFECTS: Concurrent use of ustekinumab with immunosuppressive or immunomodulating agents may result in an increased risk for serious infections.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The US manufacturer of ustekinumab recommends caution because the concurrent use of ustekinumab with immunosuppressive agents may increase the risk of infection. If concurrent therapy is warranted, consider the risk of additive immune suppression and monitor based on prescribing information for both agents.(1)
DISCUSSION: Ustekinumab has not been studied in combination with other immunosuppressants in psoriasis studies. In psoriatic arthritis studies, concomitant methotrexate use did not appear to influence the safety or efficacy of ustekinumab. In Crohn's disease and ulcerative colitis studies, concomitant use of immunosuppressants or corticosteroids did not appear to influence the safety or efficacy of ustekinumab. If concurrent therapy is warranted, consider the potential for increased immunosuppressive risks from both agents.(1) The most common infections reported by ustekinumab treated patients in the clinical trial periods included nasopharyngitis(8%) and upper respiratory tract infection(5%). Serious bacterial, mycobacterial, fungal, and viral infections were observed in patients receiving ustekinumab. Cases of interstitial pneumonia, eosinophilic pneumonia, and cryptogenic organizing pneumonia resulting in respiratory failure or prolonged hospitalization have been reported in patients receiving ustekinumab.(1)
Myelosuppressive Mod-Weak Cyp3a4 Inh/Tacrolimus
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: Moderate and weak immunosuppressive inhibitors of CYP3A4 may inhibit the metabolism of tacrolimus and increase the risk of additive immunosuppression.(1)
CLINICAL EFFECTS: Concurrent use of an immunosuppressive CYP3A4 inhibitor may result in elevated levels of and toxicity from tacrolimus, including nephrotoxicity, neurotoxicity, immunosuppression, and prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes.(1)
PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2)
PATIENT MANAGEMENT: The US manufacturer of tacrolimus recommends monitoring tacrolimus whole blood trough concentrations and reducing tacrolimus dose if needed.(1) For patients on avapritinib: this interaction applies only to gastrointestinal stromal tumor (GIST) patients on avapritinib 200 mg or 300 mg.(3) Consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting.
DISCUSSION: In a study of 26 renal transplant recipients, conjugated estrogens 3.75 mg daily increased the tacrolimus dose-corrected concentration of tacrolimus by 85.6%. Discontinuation of the conjugated estrogens led to a decrease in tacrolimus concentration of 46.6%.(4) A case report describes a 65-year-old kidney transplant recipient who was stable on tacrolimus 9 mg per day with trough levels of 5 to 7.5 ng/mL. Ten days after starting on estradiol gel 0.5 mg per day, her tacrolimus level rose to 18.3 ng/mL and serum creatinine (Scr) rose from 1.1 mg/dL at baseline to 2 mg/dL. Tacrolimus dose was reduced by 60%, and trough levels and Scr normalized after two weeks.(5) A study of 16 healthy volunteers found that elbasvir 50 mg/grazoprevir 200 mg daily increased the area-under-curve (AUC) of tacrolimus by 43%, while the maximum concentration (Cmax) of tacrolimus was decreased by 40%.(6) An analysis of FAERS data from 2004-2017, found a significant association between transplant rejection and concurrent use of tacrolimus and clotrimazole (reporting odds ration 1.92, 95% CI). A retrospective study of 7 heart transplant patients on concurrent tacrolimus and clotrimazole troche showed a significant correlation between tacrolimus trough concentration and AUC after clotrimazole discontinuation. Tacrolimus clearance and bioavailability after clotrimazole discontinuation was 2.2-fold greater (0.27 vs. 0.59 L/h/kg) and the trough concentration decreased from 6.5 ng/mL at 1 day to 5.3 ng/mL at 2 days after clotrimazole discontinuation.(7) A retrospective study of 26 heart transplant patients found that discontinuation of concurrent clotrimazole with tacrolimus in the CYP3A5 expresser group had a 3.3-fold increase in apparent oral clearance and AUC of tacrolimus (0.27 vs. 0.89 L/h/kg) compared to the CYP3A5 non expresser group with a 2.2-fold mean increase (0.18 vs. 0.39 L/h/kg).(8) A study of 6 adult kidney transplant recipients found that clotrimazole (5-day course) increased the tacrolimus AUC 250% and the blood trough concentrations doubled (27.7 ng/ml versus 27.4 ng/ml). Tacrolimus clearance decreased 60% with coadministration of clotrimazole.(9) A case report describes a 23-year-old kidney transplant recipient who was stable on tacrolimus 5 mg twice daily, mycophenolate mofetil 30 mg daily, prednisone (30 mg daily tapered over time to 5 mg), and clotrimazole troche 10 mg four times daily. Discontinuation of clotrimazole resulted in a decrease in tacrolimus trough levels from 13.7 ng/ml to 5.4 ng/ml over a period of 6 days. Clotrimazole was restarted with tacrolimus 6 mg resulting in an increased tacrolimus level of 19.2 ng/ml.(10) A retrospective study in 95 heart transplant recipients on concurrent clotrimazole and tacrolimus found a median tacrolimus dose increase of 66.7% was required after clotrimazole discontinuation. Tacrolimus trough concentration was found to have decreased 42.5% after clotrimazole discontinuation.(11) A retrospective study in 65 pancreas transplant patients on concurrent tacrolimus, clotrimazole, cyclosporine, and prednisone found that clotrimazole discontinuation at 3 months after transplantation may cause significant tacrolimus trough level reductions.(12) Moderate CYP3A4 inhibitors linked to this monograph include: duvelisib, fedratinib, imatinib, rilzabrutinib, and treosulfan.(6) Weak CYP3A4 inhibitors linked to this monograph include: asciminib, avapritinib, belumosudil, capivasertib, everolimus, larotrectinib, leflunomide, olaparib, palbociclib, and teriflunomide.(6)
Palbociclib/Proton Pump Inhibitors
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: The mechanism of this interaction is not fully understood and may involve dysbiosis or gastric pH changes resulting from proton pump inhibitors (PPIs).(1,2) The aqueous solubility of palbociclib is pH-dependent. Higher gastric pH leads to lower solubility which may reduce palbociclib absorption.(1)
CLINICAL EFFECTS: Coadministration of PPIs may reduce the bioavailability of palbociclib, leading to decreased systemic levels and effectiveness.(1) Although administration of palbociclib with food minimizes the decrease in absorption,(1) retrospective studies and a meta-analysis have found lower survival rates among patients on concurrent PPIs.(2-7)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The manufacturer of palbociclib capsules states that palbociclib should be taken with food, whereas palbociclib tablets may be taken with or without food. There are no constraints on concurrent use of proton pump inhibitors.(1) Given the decreased survival rates observed in patients who received PPIs with palbociclib, the authors of some studies on concurrent use of these agents have made various recommendations, including avoiding PPIs with palbociclib, using ribociclib instead of palbociclib, using low strengths of PPIs, or using H2-antagonists or antacids.(2-7)
DISCUSSION: Palbociclib solubility decreases significantly above pH 4.(1) In a study with healthy volunteers, rabeprazole decreased the maximum concentration (Cmax) and area-under-curve (AUC) of single-dose palbociclib without food by 80% and 62%, respectively. In another study of healthy volunteers in a fed state, rabeprazole decreased Cmax and AUC of single-dose palbociclib by 41% and 13%, respectively.(1) A systematic review and meta-analysis examined studies of HER2-negative, hormone receptor-positive patients with metastatic breast cancer treated with palbociclib or ribociclib with or without concomitant PPIs that reported on survival outcomes. Eight studies consisting of 2,584 patients (830 on PPIs, 1754 not on PPIs) were included. Patients on concurrent PPIs had a significantly higher risk of all-cause mortality (HR, 2.03; 95% CI, 1.49 to 2.77) and disease progression (HR, 1.75; 95% CI, 1.26 to 2.43) compared to patients not on PPIs, though there was a high degree of heterogeneity in disease progression.(2) A retrospective cohort of patients with advanced or metastatic breast cancer treated with palbociclib capsules (344 patients on PPIs, 966 patients not on PPIs) revealed that patients on PPIs had shorter progression-free survival (PFS) (HR 1.76 (95% CI, 1.46-2.13) and lower overall survival (HR, 2.71 [95% CI, 2.07-3.53]).(3) A post-hoc analysis of the phase 2 PARSIFAL trial evaluated PFS in patients on palbociclib capsules. 326 patients were PPI-naive, 64 patients were early users of PPIs (started on PPIs since starting palbociclib), and 91 patients were long-term users of PPIs. PPI use was associated with a shorter PFS (HR in early PPI users 1.5; 95% CI 1.1-2.2; HR in long-term PPI users 1.4; 95% CI 1.1-1.9).(4) A retrospective study of 50 patients with metastatic breast cancer on palbociclib found that concurrent PPI use was associated with a shorter PFS.(5) In an observational study of patients with metastatic breast cancer on palbociclib capsules, PFS was compared between 65 patients on PPIs and 40 patients not on PPIs. On multivariate analysis, PPI usage was an independent predictor of shorter PFS (HR 5.60; 95% confidence interval: 1.98-15.85).(6) A retrospective observational cohort of metastatic breast cancer patients on palbociclib found that patients on concurrent PPIs had a shorter PFS than those not on PPIs (14.0 versus 37.9 months, p < 0.0001).(7) In contrast to these findings, other studies have not found a detrimental effect of PPIs on palbociclib efficacy. A retrospective observational study focused on 112 patients with endocrine-resistant metastatic breast cancer on palbociclib capsules (n=58) and tablets (n=20). There was no difference in PFS in patients on concurrent PPIs compared to those not on PPIs.(8) A study looking at 82 patients with metastatic breast cancer treat 1st line with palbociclib tablets(9) and a retrospective observational study on metastatic breast cancer patients on palbociclib capsules(10) also did not find a significantly different PFS between patients with and without concurrent PPIs.
Weak Cyp3a4 Inhibitors/Lemborexant (<= 5 Mg)
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of lemborexant.(1)
CLINICAL EFFECTS: Concurrent use of an inhibitor of CYP3A4 may result in increased levels of and effects from lemborexant, including somnolence, fatigue, CNS depressant effects, daytime impairment, headache, and nightmare or abnormal dreams.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The maximum recommended dose of lemborexant with concurrent use of a weak CYP3A4 inhibitors should not exceed 5 mg per dose.(1) For patients on avapritinib: this interaction applies only to gastrointestinal stromal tumor (GIST) patients on avapritinib 200 mg or 300 mg.(2)
DISCUSSION: Lemborexant is a CYP3A4 substrate. In a PKPB model, concurrent use of lemborexant with itraconazole increased area-under-curve (AUC) and concentration maximum (Cmax) by 3.75-fold and 1.5-fold, respectively. Concurrent use of lemborexant with fluconazole increased AUC and Cmax by 4.25-fold and 1.75-fold, respectively.(1) Weak inhibitors of CYP3A4 include: amiodarone, amlodipine, anamorelin, asciminib, avapritinib, azithromycin, Baikal skullcap, belumosudil, berberine, bicalutamide, blueberry, brodalumab, camizestrant, cannabidiol, capivasertib, chlorzoxazone, cilostazol, cimetidine, ciprofloxacin, clotrimazole, cranberry, cyclosporine, daclatasvir, daridorexant, delavirdine, dihydroberberine, diosmin, elinzanetant, everolimus, flibanserin, fosaprepitant, fostamatinib, gepotidacin, ginkgo, givinostat, glecaprevir/pibrentasvir, goldenseal, grazoprevir, isoniazid, istradefylline, ivacaftor, lacidipine, lapatinib, larotrectinib, lazertinib, leflunomide, levamlodipine, linagliptin, lomitapide, lurasidone, mavorixafor, olaparib, osilodrostat, palbociclib, pazopanib, peppermint oil, piperine, propiverine, propofol, ranitidine, ranolazine, resveratrol, roxithromycin, rucaparib, selpercatinib, simeprevir, sitaxsentan, skullcap, teriflunomide, ticagrelor, tolvaptan, trofinetide, vepdegestrant, viloxazine, vonoprazan, and ziftomenib.(1,3)
Weak Cyp3a4 Inhibitors/Ubrogepant (<= 50 Mg)
SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.
MECHANISM OF ACTION: Weak inhibitors of CYP3A4 may inhibit the metabolism of ubrogepant.(1)
CLINICAL EFFECTS: Concurrent use of ubrogepant with weak CYP3A4 inhibitors may result in an increase in exposure of ubrogepant.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: The manufacturer recommends a dosage adjustment of ubrogepant when used concomitantly with weak CYP3A4 inhibitors. Initial dose of ubrogepant should not exceed 50 mg when used concomitantly with weak inhibitors of CYP3A4. A second dose may be given within 24 hours but should not exceed 50 mg when used concurrently with weak CYP3A4 inhibitors.(1) For patients on avapritinib: this interaction applies only to gastrointestinal stromal tumor (GIST) patients on avapritinib 200 mg or 300 mg.(2)
DISCUSSION: Coadministration of ubrogepant with verapamil, a moderate CYP3A4 inhibitor, resulted in a 3.5-fold and 2.8-fold increase in area-under-curve (AUC) and concentration maximum (Cmax), respectively. No dedicated drug interaction study was conducted to assess concomitant use with weak CYP3A4 inhibitors. The conservative prediction of the maximal potential increase in ubrogepant exposure with weak CYP3A4 inhibitors is not expected to be more than 2-fold.(1) Weak inhibitors of CYP3A4 include: amiodarone, amlodipine, anamorelin, asciminib, avapritinib, azithromycin, Baikal skullcap, berberine, bicalutamide, blueberry, brodalumab, camizestrant, cannabidiol, capivasertib, chlorzoxazone, cilostazol, cimetidine, ciprofloxacin, clotrimazole, cranberry, cyclosporine, daclatasvir, delavirdine, deutivacaftor, dihydroberberine, diosmin, elinzanetant, everolimus, flibanserin, fosaprepitant, fostamatinib, gepotidacin, givinostat, glecaprevir/pibrentasvir, goldenseal, grazoprevir, isoniazid, istradefylline, ivacaftor, lacidipine, lapatinib, larotrectinib, lazertinib, leflunomide, levamlodipine, linagliptin, lomitapide, lurasidone, maribavir, mavorixafor, olaparib, osilodrostat, palbociclib, pazopanib, peppermint oil, piperine, pirtobrutinib, propiverine, propofol, ranitidine, ranolazine, resveratrol, roxithromycin, simeprevir, sitaxsentan, skullcap, teriflunomide, ticagrelor, tolvaptan, trofinetide, vepdegestrant, viloxazine, vonoprazan, and ziftomenib.(3,4)
Contraindications
*None.
- Lactation
- Child-pugh class C hepatic impairment
- Disease of liver
- Interstitial lung disease
- Neutropenic disorder
- Pregnancy
- Severe infection
- Thromboembolic disorder
There are no moderate contraindications for this drug.
Adverse reactions
The most common adverse effects (>=20%) of palbociclib in combination with either letrozole or fulvestrant included decreased white blood cell count, decreased neutrophils, increased creatinine, decreased hemoglobin, decreased platelets, infections, increased AST and ALT, fatigue, nausea, stomatitis, diarrhea, and alopecia.
The most common adverse effects (>=20%) of palbociclib in combination with inavolisib and fulvestrant included decreased neutrophils, decreased hemoglobin, increased fasting glucose, decreased platelets, decreased lymphocytes, stomatitis, diarrhea, decreased calcium, fatigue, decreased potassium, increased creatinine, increased ALT, nausea, decreased sodium, decreased magnesium, rash, decreased appetite, COVID-19 infection, and headache.
More Frequent
- Abnormal hepatic function tests
- Anemia
- Infection
- Leukopenia
- Neutropenic disorder
- Thrombocytopenic disorder
Less Frequent
- Increased alanine transaminase
- Increased aspartate transaminase
- Thromboembolic disorder
Rare or Very Rare
- Erythema multiforme
- Interstitial lung disease
- Interstitial pneumonitis
- Palmar-plantar erythrodysesthesia
- Venous thrombosis
More Frequent
- Alopecia
- Anorexia
- Diarrhea
- Epistaxis
- Fatigue
- Fever
- General weakness
- Headache disorder
- Hypocalcemia
- Increased alkaline phosphatase
- Muscle spasm
- Nausea
- Pruritus of skin
- Skin rash
- Stomatitis
- Upper respiratory infection
- Vomiting
Less Frequent
- Blurred vision
- Dry eye
- Dry skin
- Dysgeusia
- Eye tearing
- Hyperglycemia
Precautions
No enhanced messaging available.
Safety and efficacy of palbociclib have not been established in pediatric patients younger than 18 years of age. Safety and efficacy were assessed (not established) in 3 open-label trials including 140 pediatric patients (<17 years of age); no new safety signals occurred and palbociclib exposure in patients administered the drug as monotherapy or in combination were within range of those seen in adults administered a similar dosed based on body surface area.
Altered glucose metabolism associated with pancreatic islet cell vacuolation, cataracts, ocular lens degeneration, renal tubule vacuolation, chronic progressive nephropathy, and atrophy of adipose tissue have been observed in immature animals receiving palbociclib for 27 weeks (at exposure levels approximately 11 times the AUC in humans at the recommended dosage); tooth abnormalities (i.e., discoloration, ameloblast degeneration or necrosis, mononuclear cell infiltrate) also have been observed in animals receiving palbociclib at exposure levels approximately 15 times the AUC in humans at the recommended dosage.
Palbociclib may cause fetal harm if administered to pregnant women based on its mechanism of action and animal findings. Pregnancy should be avoided during palbociclib therapy. The manufacturer recommends confirmation of pregnancy status prior to initiation of palbociclib, and women of childbearing potential should be advised to use an effective method of contraception while receiving palbociclib and for at least 3 weeks after discontinuance of therapy.
It is not known whether palbociclib is distributed into human milk. Because many drugs are distributed into human milk and because of the potential for serious adverse reactions to palbociclib in nursing infants, women should be advised to discontinue nursing during therapy and for 3 weeks after discontinuance of the drug. The effects of the drug on nursing infants or on milk production are unknown.
The manufacturer makes no specific dosage recommendations for geriatric patients.
In the PALOMA-2 study, 41% of palbociclib-treated patients were >=65 years of age and 11% were >=75 years of age. In the PALOMA-3 study, 25% of palbociclib-treated patients were >=65 years of age and 8% were >=75 years of age. No overall differences in safety and efficacy were observed between geriatric and younger patients.
ICD codes
| Code | Type | Description |
|---|---|---|
| Hormone receptor (Hr)-positive, HEr2-negative advanced breast cancer | ||
| C50 | ICD10CM | Malignant neoplasm of breast |
| C50.1 | ICD10CM | Malignant neoplasm of central portion of breast |
| C50.11 | ICD10CM | Malignant neoplasm of central portion of breast, female |
| C50.111 | ICD10CM | Malignant neoplasm of central portion of right female breast |
| C50.112 | ICD10CM | Malignant neoplasm of central portion of left female breast |
| C50.119 | ICD10CM | Malignant neoplasm of central portion of unspecified female breast |
| C50.12 | ICD10CM | Malignant neoplasm of central portion of breast, male |
| C50.121 | ICD10CM | Malignant neoplasm of central portion of right male breast |
| C50.122 | ICD10CM | Malignant neoplasm of central portion of left male breast |
| C50.129 | ICD10CM | Malignant neoplasm of central portion of unspecified male breast |
| C50.2 | ICD10CM | Malignant neoplasm of upper-inner quadrant of breast |
| C50.21 | ICD10CM | Malignant neoplasm of upper-inner quadrant of breast, female |
| C50.211 | ICD10CM | Malignant neoplasm of upper-inner quadrant of right female breast |
| C50.212 | ICD10CM | Malignant neoplasm of upper-inner quadrant of left female breast |
| C50.219 | ICD10CM | Malignant neoplasm of upper-inner quadrant of unspecified female breast |
| C50.22 | ICD10CM | Malignant neoplasm of upper-inner quadrant of breast, male |
| C50.221 | ICD10CM | Malignant neoplasm of upper-inner quadrant of right male breast |
| C50.222 | ICD10CM | Malignant neoplasm of upper-inner quadrant of left male breast |
| C50.229 | ICD10CM | Malignant neoplasm of upper-inner quadrant of unspecified male breast |
| C50.3 | ICD10CM | Malignant neoplasm of lower-inner quadrant of breast |
| C50.31 | ICD10CM | Malignant neoplasm of lower-inner quadrant of breast, female |
| C50.311 | ICD10CM | Malignant neoplasm of lower-inner quadrant of right female breast |
| C50.312 | ICD10CM | Malignant neoplasm of lower-inner quadrant of left female breast |
| C50.319 | ICD10CM | Malignant neoplasm of lower-inner quadrant of unspecified female breast |
| C50.32 | ICD10CM | Malignant neoplasm of lower-inner quadrant of breast, male |
| C50.321 | ICD10CM | Malignant neoplasm of lower-inner quadrant of right male breast |
| C50.322 | ICD10CM | Malignant neoplasm of lower-inner quadrant of left male breast |
| C50.329 | ICD10CM | Malignant neoplasm of lower-inner quadrant of unspecified male breast |
| C50.4 | ICD10CM | Malignant neoplasm of upper-outer quadrant of breast |
| C50.41 | ICD10CM | Malignant neoplasm of upper-outer quadrant of breast, female |
| C50.411 | ICD10CM | Malignant neoplasm of upper-outer quadrant of right female breast |
| C50.412 | ICD10CM | Malignant neoplasm of upper-outer quadrant of left female breast |
| C50.419 | ICD10CM | Malignant neoplasm of upper-outer quadrant of unspecified female breast |
| C50.42 | ICD10CM | Malignant neoplasm of upper-outer quadrant of breast, male |
| C50.421 | ICD10CM | Malignant neoplasm of upper-outer quadrant of right male breast |
| C50.422 | ICD10CM | Malignant neoplasm of upper-outer quadrant of left male breast |
| C50.429 | ICD10CM | Malignant neoplasm of upper-outer quadrant of unspecified male breast |
| C50.5 | ICD10CM | Malignant neoplasm of lower-outer quadrant of breast |
| C50.51 | ICD10CM | Malignant neoplasm of lower-outer quadrant of breast, female |
| C50.511 | ICD10CM | Malignant neoplasm of lower-outer quadrant of right female breast |
| C50.512 | ICD10CM | Malignant neoplasm of lower-outer quadrant of left female breast |
| C50.519 | ICD10CM | Malignant neoplasm of lower-outer quadrant of unspecified female breast |
| C50.52 | ICD10CM | Malignant neoplasm of lower-outer quadrant of breast, male |
| C50.521 | ICD10CM | Malignant neoplasm of lower-outer quadrant of right male breast |
| C50.522 | ICD10CM | Malignant neoplasm of lower-outer quadrant of left male breast |
| C50.529 | ICD10CM | Malignant neoplasm of lower-outer quadrant of unspecified male breast |
| C50.6 | ICD10CM | Malignant neoplasm of axillary tail of breast |
| C50.61 | ICD10CM | Malignant neoplasm of axillary tail of breast, female |
| C50.611 | ICD10CM | Malignant neoplasm of axillary tail of right female breast |
| C50.612 | ICD10CM | Malignant neoplasm of axillary tail of left female breast |
| C50.619 | ICD10CM | Malignant neoplasm of axillary tail of unspecified female breast |
| C50.62 | ICD10CM | Malignant neoplasm of axillary tail of breast, male |
| C50.621 | ICD10CM | Malignant neoplasm of axillary tail of right male breast |
| C50.622 | ICD10CM | Malignant neoplasm of axillary tail of left male breast |
| C50.629 | ICD10CM | Malignant neoplasm of axillary tail of unspecified male breast |
| C50.8 | ICD10CM | Malignant neoplasm of overlapping sites of breast |
| C50.81 | ICD10CM | Malignant neoplasm of overlapping sites of breast, female |
| C50.811 | ICD10CM | Malignant neoplasm of overlapping sites of right female breast |
| C50.812 | ICD10CM | Malignant neoplasm of overlapping sites of left female breast |
| C50.819 | ICD10CM | Malignant neoplasm of overlapping sites of unspecified female breast |
| C50.82 | ICD10CM | Malignant neoplasm of overlapping sites of breast, male |
| C50.821 | ICD10CM | Malignant neoplasm of overlapping sites of right male breast |
| C50.822 | ICD10CM | Malignant neoplasm of overlapping sites of left male breast |
| C50.829 | ICD10CM | Malignant neoplasm of overlapping sites of unspecified male breast |
| C50.9 | ICD10CM | Malignant neoplasm of breast of unspecified site |
| C50.91 | ICD10CM | Malignant neoplasm of breast of unspecified site, female |
| C50.911 | ICD10CM | Malignant neoplasm of unspecified site of right female breast |
| C50.912 | ICD10CM | Malignant neoplasm of unspecified site of left female breast |
| C50.919 | ICD10CM | Malignant neoplasm of unspecified site of unspecified female breast |
| C50.92 | ICD10CM | Malignant neoplasm of breast of unspecified site, male |
| C50.921 | ICD10CM | Malignant neoplasm of unspecified site of right male breast |
| C50.922 | ICD10CM | Malignant neoplasm of unspecified site of left male breast |
| C50.929 | ICD10CM | Malignant neoplasm of unspecified site of unspecified male breast |
| Z17.0 | ICD10CM | Estrogen receptor positive status [Er+] |
| Z19.1 | ICD10CM | Hormone sensitive malignancy status |
| Hormone receptor (Hr)-positive, HEr2-negative, PIk3CA mutated advanced breast cancer | ||
| C50 | ICD10CM | Malignant neoplasm of breast |
| C50.1 | ICD10CM | Malignant neoplasm of central portion of breast |
| C50.11 | ICD10CM | Malignant neoplasm of central portion of breast, female |
| C50.111 | ICD10CM | Malignant neoplasm of central portion of right female breast |
| C50.112 | ICD10CM | Malignant neoplasm of central portion of left female breast |
| C50.119 | ICD10CM | Malignant neoplasm of central portion of unspecified female breast |
| C50.12 | ICD10CM | Malignant neoplasm of central portion of breast, male |
| C50.121 | ICD10CM | Malignant neoplasm of central portion of right male breast |
| C50.122 | ICD10CM | Malignant neoplasm of central portion of left male breast |
| C50.129 | ICD10CM | Malignant neoplasm of central portion of unspecified male breast |
| C50.2 | ICD10CM | Malignant neoplasm of upper-inner quadrant of breast |
| C50.21 | ICD10CM | Malignant neoplasm of upper-inner quadrant of breast, female |
| C50.211 | ICD10CM | Malignant neoplasm of upper-inner quadrant of right female breast |
| C50.212 | ICD10CM | Malignant neoplasm of upper-inner quadrant of left female breast |
| C50.219 | ICD10CM | Malignant neoplasm of upper-inner quadrant of unspecified female breast |
| C50.22 | ICD10CM | Malignant neoplasm of upper-inner quadrant of breast, male |
| C50.221 | ICD10CM | Malignant neoplasm of upper-inner quadrant of right male breast |
| C50.222 | ICD10CM | Malignant neoplasm of upper-inner quadrant of left male breast |
| C50.229 | ICD10CM | Malignant neoplasm of upper-inner quadrant of unspecified male breast |
| C50.3 | ICD10CM | Malignant neoplasm of lower-inner quadrant of breast |
| C50.31 | ICD10CM | Malignant neoplasm of lower-inner quadrant of breast, female |
| C50.311 | ICD10CM | Malignant neoplasm of lower-inner quadrant of right female breast |
| C50.312 | ICD10CM | Malignant neoplasm of lower-inner quadrant of left female breast |
| C50.319 | ICD10CM | Malignant neoplasm of lower-inner quadrant of unspecified female breast |
| C50.32 | ICD10CM | Malignant neoplasm of lower-inner quadrant of breast, male |
| C50.321 | ICD10CM | Malignant neoplasm of lower-inner quadrant of right male breast |
| C50.322 | ICD10CM | Malignant neoplasm of lower-inner quadrant of left male breast |
| C50.329 | ICD10CM | Malignant neoplasm of lower-inner quadrant of unspecified male breast |
| C50.4 | ICD10CM | Malignant neoplasm of upper-outer quadrant of breast |
| C50.41 | ICD10CM | Malignant neoplasm of upper-outer quadrant of breast, female |
| C50.411 | ICD10CM | Malignant neoplasm of upper-outer quadrant of right female breast |
| C50.412 | ICD10CM | Malignant neoplasm of upper-outer quadrant of left female breast |
| C50.419 | ICD10CM | Malignant neoplasm of upper-outer quadrant of unspecified female breast |
| C50.42 | ICD10CM | Malignant neoplasm of upper-outer quadrant of breast, male |
| C50.421 | ICD10CM | Malignant neoplasm of upper-outer quadrant of right male breast |
| C50.422 | ICD10CM | Malignant neoplasm of upper-outer quadrant of left male breast |
| C50.429 | ICD10CM | Malignant neoplasm of upper-outer quadrant of unspecified male breast |
| C50.5 | ICD10CM | Malignant neoplasm of lower-outer quadrant of breast |
| C50.51 | ICD10CM | Malignant neoplasm of lower-outer quadrant of breast, female |
| C50.511 | ICD10CM | Malignant neoplasm of lower-outer quadrant of right female breast |
| C50.512 | ICD10CM | Malignant neoplasm of lower-outer quadrant of left female breast |
| C50.519 | ICD10CM | Malignant neoplasm of lower-outer quadrant of unspecified female breast |
| C50.52 | ICD10CM | Malignant neoplasm of lower-outer quadrant of breast, male |
| C50.521 | ICD10CM | Malignant neoplasm of lower-outer quadrant of right male breast |
| C50.522 | ICD10CM | Malignant neoplasm of lower-outer quadrant of left male breast |
| C50.529 | ICD10CM | Malignant neoplasm of lower-outer quadrant of unspecified male breast |
| C50.6 | ICD10CM | Malignant neoplasm of axillary tail of breast |
| C50.61 | ICD10CM | Malignant neoplasm of axillary tail of breast, female |
| C50.611 | ICD10CM | Malignant neoplasm of axillary tail of right female breast |
| C50.612 | ICD10CM | Malignant neoplasm of axillary tail of left female breast |
| C50.619 | ICD10CM | Malignant neoplasm of axillary tail of unspecified female breast |
| C50.62 | ICD10CM | Malignant neoplasm of axillary tail of breast, male |
| C50.621 | ICD10CM | Malignant neoplasm of axillary tail of right male breast |
| C50.622 | ICD10CM | Malignant neoplasm of axillary tail of left male breast |
| C50.629 | ICD10CM | Malignant neoplasm of axillary tail of unspecified male breast |
| C50.8 | ICD10CM | Malignant neoplasm of overlapping sites of breast |
| C50.81 | ICD10CM | Malignant neoplasm of overlapping sites of breast, female |
| C50.811 | ICD10CM | Malignant neoplasm of overlapping sites of right female breast |
| C50.812 | ICD10CM | Malignant neoplasm of overlapping sites of left female breast |
| C50.819 | ICD10CM | Malignant neoplasm of overlapping sites of unspecified female breast |
| C50.82 | ICD10CM | Malignant neoplasm of overlapping sites of breast, male |
| C50.821 | ICD10CM | Malignant neoplasm of overlapping sites of right male breast |
| C50.822 | ICD10CM | Malignant neoplasm of overlapping sites of left male breast |
| C50.829 | ICD10CM | Malignant neoplasm of overlapping sites of unspecified male breast |
| C50.9 | ICD10CM | Malignant neoplasm of breast of unspecified site |
| C50.91 | ICD10CM | Malignant neoplasm of breast of unspecified site, female |
| C50.911 | ICD10CM | Malignant neoplasm of unspecified site of right female breast |
| C50.912 | ICD10CM | Malignant neoplasm of unspecified site of left female breast |
| C50.919 | ICD10CM | Malignant neoplasm of unspecified site of unspecified female breast |
| C50.92 | ICD10CM | Malignant neoplasm of breast of unspecified site, male |
| C50.921 | ICD10CM | Malignant neoplasm of unspecified site of right male breast |
| C50.922 | ICD10CM | Malignant neoplasm of unspecified site of left male breast |
| C50.929 | ICD10CM | Malignant neoplasm of unspecified site of unspecified male breast |
| Z17.0 | ICD10CM | Estrogen receptor positive status [Er+] |
| Z19.1 | ICD10CM | Hormone sensitive malignancy status |
| Hormone receptor (Hr)-positive, HEr2-positive breast cancer | ||
| C50.011 | ICD10CM | Malignant neoplasm of nipple and areola, right female breast |
| C50.012 | ICD10CM | Malignant neoplasm of nipple and areola, left female breast |
| C50.019 | ICD10CM | Malignant neoplasm of nipple and areola, unspecified female breast |
| C50.021 | ICD10CM | Malignant neoplasm of nipple and areola, right male breast |
| C50.022 | ICD10CM | Malignant neoplasm of nipple and areola, left male breast |
| C50.029 | ICD10CM | Malignant neoplasm of nipple and areola, unspecified male breast |
| C50.111 | ICD10CM | Malignant neoplasm of central portion of right female breast |
| C50.112 | ICD10CM | Malignant neoplasm of central portion of left female breast |
| C50.119 | ICD10CM | Malignant neoplasm of central portion of unspecified female breast |
| C50.121 | ICD10CM | Malignant neoplasm of central portion of right male breast |
| C50.122 | ICD10CM | Malignant neoplasm of central portion of left male breast |
| C50.129 | ICD10CM | Malignant neoplasm of central portion of unspecified male breast |
| C50.211 | ICD10CM | Malignant neoplasm of upper-inner quadrant of right female breast |
| C50.212 | ICD10CM | Malignant neoplasm of upper-inner quadrant of left female breast |
| C50.219 | ICD10CM | Malignant neoplasm of upper-inner quadrant of unspecified female breast |
| C50.221 | ICD10CM | Malignant neoplasm of upper-inner quadrant of right male breast |
| C50.222 | ICD10CM | Malignant neoplasm of upper-inner quadrant of left male breast |
| C50.229 | ICD10CM | Malignant neoplasm of upper-inner quadrant of unspecified male breast |
| C50.311 | ICD10CM | Malignant neoplasm of lower-inner quadrant of right female breast |
| C50.312 | ICD10CM | Malignant neoplasm of lower-inner quadrant of left female breast |
| C50.319 | ICD10CM | Malignant neoplasm of lower-inner quadrant of unspecified female breast |
| C50.321 | ICD10CM | Malignant neoplasm of lower-inner quadrant of right male breast |
| C50.322 | ICD10CM | Malignant neoplasm of lower-inner quadrant of left male breast |
| C50.329 | ICD10CM | Malignant neoplasm of lower-inner quadrant of unspecified male breast |
| C50.411 | ICD10CM | Malignant neoplasm of upper-outer quadrant of right female breast |
| C50.412 | ICD10CM | Malignant neoplasm of upper-outer quadrant of left female breast |
| C50.419 | ICD10CM | Malignant neoplasm of upper-outer quadrant of unspecified female breast |
| C50.421 | ICD10CM | Malignant neoplasm of upper-outer quadrant of right male breast |
| C50.422 | ICD10CM | Malignant neoplasm of upper-outer quadrant of left male breast |
| C50.429 | ICD10CM | Malignant neoplasm of upper-outer quadrant of unspecified male breast |
| C50.511 | ICD10CM | Malignant neoplasm of lower-outer quadrant of right female breast |
| C50.512 | ICD10CM | Malignant neoplasm of lower-outer quadrant of left female breast |
| C50.519 | ICD10CM | Malignant neoplasm of lower-outer quadrant of unspecified female breast |
| C50.521 | ICD10CM | Malignant neoplasm of lower-outer quadrant of right male breast |
| C50.522 | ICD10CM | Malignant neoplasm of lower-outer quadrant of left male breast |
| C50.529 | ICD10CM | Malignant neoplasm of lower-outer quadrant of unspecified male breast |
| C50.611 | ICD10CM | Malignant neoplasm of axillary tail of right female breast |
| C50.612 | ICD10CM | Malignant neoplasm of axillary tail of left female breast |
| C50.619 | ICD10CM | Malignant neoplasm of axillary tail of unspecified female breast |
| C50.621 | ICD10CM | Malignant neoplasm of axillary tail of right male breast |
| C50.622 | ICD10CM | Malignant neoplasm of axillary tail of left male breast |
| C50.629 | ICD10CM | Malignant neoplasm of axillary tail of unspecified male breast |
| C50.811 | ICD10CM | Malignant neoplasm of overlapping sites of right female breast |
| C50.812 | ICD10CM | Malignant neoplasm of overlapping sites of left female breast |
| C50.819 | ICD10CM | Malignant neoplasm of overlapping sites of unspecified female breast |
| C50.821 | ICD10CM | Malignant neoplasm of overlapping sites of right male breast |
| C50.822 | ICD10CM | Malignant neoplasm of overlapping sites of left male breast |
| C50.829 | ICD10CM | Malignant neoplasm of overlapping sites of unspecified male breast |
| C50.911 | ICD10CM | Malignant neoplasm of unspecified site of right female breast |
| C50.912 | ICD10CM | Malignant neoplasm of unspecified site of left female breast |
| C50.919 | ICD10CM | Malignant neoplasm of unspecified site of unspecified female breast |
| C50.921 | ICD10CM | Malignant neoplasm of unspecified site of right male breast |
| C50.922 | ICD10CM | Malignant neoplasm of unspecified site of left male breast |
| C50.929 | ICD10CM | Malignant neoplasm of unspecified site of unspecified male breast |
| C50.A0 | ICD10CM | Malignant inflammatory neoplasm of unspecified breast |
| C50.A1 | ICD10CM | Malignant inflammatory neoplasm of right breast |
| C50.A2 | ICD10CM | Malignant inflammatory neoplasm of left breast |
ICD code information from First Databank (FDB).
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Last reviewed · Source: First Databank (FDB) drug data
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