Cefaclor (cefaclor)

Cefaclor is commercially available as the monohydrate; dosage is expressed in terms of anhydrous cefaclor.

Modification of usual cefaclor dosage is not necessary in patients with renal impairment; however, close clinical observation and appropriate laboratory tests are recommended in patients with moderate or severe renal impairment since experience in such patients is limited.

No dosing information is available for this tab.

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

Antibiotics/Fecal Microbiota

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: Fecal microbiota is a suspension of live bacteria, which may be compromised by concurrent use of antibiotics.(1)

CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota. Antibacterial treatment should be completed for 24 to 72 hours before initiating treatment with fecal microbiota. Do not use antibiotics for up to 8 weeks after fecal microbiota.(1)

DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota.

Antibiotics/Fecal Microbiota Spores

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: Fecal microbiota spores is a suspension of live bacterial spores, which may be compromised by concurrent use of antibiotics.(1)

CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota spores.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota spores. Antibacterial treatment should be completed for 2 to 4 days before initiating treatment with fecal microbiota spores.(1)

DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota spores.

Antimicrobials/Live Typhoid Vaccine

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: The antimicrobial may be active against the organism in the live-vaccine. Antimicrobial therapy may prevent the vaccine organism from replicating enough to trigger an immune response.(1)

CLINICAL EFFECTS: Vaccination may be ineffective.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Do not give oral typhoid vaccine until 72 hours after the last dose of antimicrobial. If possible, to optimize vaccine effectiveness, do not start antibacterial drugs for 72 hours after the last dose of oral typhoid vaccine. A longer interval should be considered for long-acting antimicrobials, such as azithromycin.(3)

DISCUSSION: Because antimicrobial therapy may prevent sufficient vaccine-organism replication to generate an immune response, the manufacturer of live-attenuated typhoid vaccine and the Centers for Disease Control (CDC) state that the vaccine should not be administered to patients receiving antimicrobial therapy.(1-3)

There are no severe interactions for this drug.

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

Selected Cephalosporins & Penicillins/Probenecid

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

MECHANISM OF ACTION: Probenecid impairs the clearance of some cephalosporins and penicillins via inhibition of renal anion transporters in the proximal tubule.(49) It has also been hypothesized that probenecid may affect tissue distribution of cephalosporins.(1-5)

CLINICAL EFFECTS: The concurrent administration of probenecid may result in increased maximum concentration (Cmax), area-under-curve (AUC), and half-life of the cephalosporin or penicillin.(49) While this may improve antibiotic efficacy,(46-48) increased levels may also increase the risk for antibiotic-associated nephrotoxicity.(4)

PREDISPOSING FACTORS: Underlying renal dysfunction may increase the risk for nephrotoxicity.

PATIENT MANAGEMENT: In patients receiving the combination to improve antibiotic efficacy, monitor for antibiotic adverse effects and consider monitoring renal function. In patients receiving probenecid therapy to prevent or treat hyperuricemia, exposure to the antibiotic will be increased. A decrease in antibiotic dose or frequency may be required. The US manufacturer of piperacillin-tazobactam states probenecid should not be coadministered with piperacillin-tazobactam unless the benefit outweighs the risk.(50)

DISCUSSION: Concurrent use of probenecid with a cephalosporin or penicillin may cause an increase in the Cmax, AUC, and an increased elimination half life of the antibiotic.(6-8,49) This may be beneficial or necessary in difficult to treat infections,(46-48) but an increased risk for adverse effects should be expected. Antibiotics not dose adjusted for concurrent use with probenecid may be associated with an increased risk for adverse effects, such as nephrotoxicity. Probenecid administered concurrently with piperacillin-tazobactam prolongs the half-life of piperacillin by 21% and tazobactam by 71%. In a study in 8 healthy males, concurrent administration of probenecid (1 g) with piperacillin (1 g IM) increased piperacillin's Cmax and AUC by 30% and 60%. Renal clearance was reduced by 40%.(51) The cephalosporins affected by probenecid include cefazolin,(9-11) cephacetrile,(12,13) cephaloglycin,(14,15) cephalexin,(16-21) cephradine, (22-23) cefoxitin,(24-28) cefadroxil(29), cefaclor,(23) cefamandole,(30) ceftizoxime,(31,32) cefuroxime,(33,34) cefprozil,(35) cefonicid,(36) cefmetazole,(37) cefmenoxime,(38) and cefditoren.(39) Probenecid has been shown not to affect moxalactam,(4,40,41) ceforanide, (4,42), cefoperazone, ceftazidime(4,34,43) or ceftriaxone.(4)

Selected Cephalosporins/Aluminum; Magnesium Compounds

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

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

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

PREDISPOSING FACTORS: None determined.

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

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

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

• Clostridioides difficile infection

There are no moderate contraindications for this drug.

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More Frequent

• Serum sickness

Rare or Very Rare

• Anaphylaxis
• Angioedema
• Clostridioides difficile infection
• Drug fever
• Erythema
• Erythema multiforme
• Hemolytic anemia
• Hypoprothrombinemia
• Kidney disease with reduction in glomerular filtration rate (GFr)
• Pruritus of skin
• Seizure disorder
• Skin rash
• Stevens-johnson syndrome

More Frequent

• Vulvovaginal candidiasis

Less Frequent

• Abdominal pain with cramps
• Diarrhea
• Nausea
• Oral candidiasis
• Vomiting

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No enhanced messaging available.

Reproduction studies in mice, rats, and ferrets using doses up to 3-5 times the maximum human dosage (1500 mg daily) based on mg/m2 have not revealed evidence of harm to the fetus. There are no adequate and controlled studies using cefaclor in pregnant women or during labor and delivery, and the drug should be used during pregnancy only when clearly needed.

Because low concentrations of cefaclor (0.16-0.21 mcg/mL) have been detected in milk following a single 500-mg oral dose of the drug, cefaclor should be used with caution in nursing women.

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