KEFTAB
Clinical safety rating: caution
Comprehensive clinical and safety monograph for KEFTAB (KEFTAB).
Cephalexin binds to penicillin-binding proteins (PBPs) on the bacterial cell wall, inhibiting transpeptidation and disrupting peptidoglycan cross-linking, leading to cell lysis via autolytic enzymes.
| Metabolism | Cephalexin is poorly metabolized; less than 5% undergoes hepatic metabolism. Primarily eliminated unchanged via renal tubular secretion and glomerular filtration. |
| Excretion | Renal: 90-95% unchanged via glomerular filtration and tubular secretion; biliary/fecal: <5% |
| Half-life | 0.8-1.2 hours (prolonged to 6-8 hours in renal impairment; requires dose adjustment for CrCl <50 mL/min) |
| Protein binding | 65-80% (primarily to serum albumin) |
| Volume of Distribution | 0.2-0.3 L/kg (indicates limited extravascular distribution; confined to extracellular fluid space) |
| Bioavailability | Oral: 85-95% (well absorbed; food delays absorption but does not reduce extent); IM: >90% |
| Onset of Action | IV: immediate; IM: 15-30 minutes; Oral: 30-60 minutes |
| Duration of Action | 6-8 hours (dose-dependent; prolonged in renal impairment; recommended dosing every 12-24 hours in CKD) |
| Molecular Weight | 365.41 |
Cefuroxime axetil (KEFTAB) 250-500 mg orally twice daily for 7-10 days. For uncomplicated urinary tract infections: 250 mg twice daily; for acute otitis media: 500 mg twice daily.
| Dosage form | TABLET |
| Renal impairment | CrCl 30-50 mL/min: dose every 12 hours; CrCl 10-29 mL/min: dose every 24 hours; CrCl <10 mL/min: dose every 48 hours; hemodialysis: 250 mg after each dialysis session. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment; no data for severe impairment (Child-Pugh Class C). |
| Pediatric use | Children (3 months to 12 years): acute otitis media or impetigo: 15 mg/kg/dose (max 500 mg) twice daily for 10 days; pharyngitis/tonsillitis: 10 mg/kg/dose (max 250 mg) twice daily for 10 days. |
| Geriatric use | Use with caution due to age-related renal decline; adjust dose based on creatinine clearance. No specific geriatric dose adjustment beyond renal adjustment. |
| 1st trimester | Avoid during first trimester unless benefits outweigh risks; cephalosporins are generally considered low risk but data limited. |
| 2nd trimester | Use with caution only if clearly needed; no evidence of harm in animal studies. |
| 3rd trimester | Use with caution; potential for disruption of infant gut flora if used near term. |
Clinical note
Comprehensive clinical and safety monograph for KEFTAB (KEFTAB).
| Placental transfer | Cefalexin crosses the placenta; fetal serum concentrations reach approximately 50% of maternal levels. |
| Breastfeeding | Cefalexin (Keftab) is excreted into breast milk in small amounts. It is generally considered compatible with breastfeeding. Monitor infant for diarrhea, rash, or allergic reaction. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Known hypersensitivity to cephalosporinsHistory of severe immediate reaction (e.g., anaphylaxis) to penicillins or other beta-lactams
| Precautions | Serious hypersensitivity reactions (anaphylaxis) have been reported, especially in penicillin-allergic patients. Clostridioides difficile-associated diarrhea (CDAD) can occur. Prolonged use may result in overgrowth of non-susceptible organisms. Dosage adjustment is required in renal impairment (CrCl < 50 mL/min). Use with caution in patients with a history of gastrointestinal disease, particularly colitis. |
| Food/Dietary | Absorption is increased when taken with food or milk; avoid taking on an empty stomach. Alcohol should be avoided during therapy and for 72 hours after the last dose due to risk of disulfiram-like reaction (flushing, headache, nausea, vomiting). |
Loading safety data…
| L1 (Safe) |
| Teratogenic Risk | Category B: Animal reproduction studies have not demonstrated fetal risk, but no adequate human studies in pregnant women. First trimester: no evidence of teratogenicity. Second and third trimesters: safe for use when indicated; theoretical risk of kernicterus in neonates if administered near term due to bilirubin displacement from albumin binding sites. |
| Fetal Monitoring | No specific fetal monitoring required. Maternal renal function should be assessed prior to and during therapy, especially in patients with renal impairment or preeclampsia. Monitor for signs of superinfection or Clostridium difficile-associated diarrhea. |
| Fertility Effects | No known adverse effects on human fertility. Animal studies have not shown impaired fertility. |
| Clinical Pearls | KEFTAB (cefuroxime axetil) is a second-generation cephalosporin with activity against Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and some anaerobes. It is a prodrug that is hydrolyzed to cefuroxime after absorption. It has poor enteral absorption; take with food to increase bioavailability. Not effective against atypical pathogens (e.g., Mycoplasma, Chlamydia). Use with caution in penicillin-allergic patients (cross-reactivity ~5-10%). Dose adjustment required in renal impairment (CrCl <30 mL/min: prolong dosing interval to every 12 hours). Monitor for C. difficile diarrhea. |
| Patient Advice | Take KEFTAB exactly as prescribed; complete the full course even if you feel better. · Take this medication with food or milk to improve absorption and reduce stomach upset. · Shake the oral suspension well before each use. Use a proper measuring device for liquid doses. · Do not take if you have a severe allergy to penicillin or cephalosporins; inform your doctor of all allergies. · Common side effects include diarrhea, nausea, and vaginal yeast infection. Contact your doctor if you have severe diarrhea, rash, or difficulty breathing. · Avoid alcohol while taking this medication and for 72 hours after the last dose to prevent a disulfiram-like reaction. · Store tablets and suspension at room temperature away from moisture and heat. Discard any unused suspension after 10 days. |