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ANTIINFECTIVES FOR SYSTEMIC USE › ANTIBACTERIALS FOR SYSTEMIC USE › OTHER BETA-LACTAM ANTIBACTERIALS › First-generation cephalosporins
cefalexin
J01DB01
Forms & Strengths
- Capsules: 250mg, 333mg, 500mg, 750mg
- Tablets: 250mg, 500mg, 750mg, 1000mg
- Oral suspension: 125mg/5mL, 250mg/5mL
Adult Dosing
- Uncomplicated urinary tract infections: 250mg every 6 hours or 500mg every 12 hours
- Skin and soft tissue infections: 250mg every 6 hours or 500mg every 12 hours
- Respiratory tract infections: 250mg every 6 hours or 500mg every 12 hours
- Maximum dose: 4g/day
Pediatric Dosing
- General dosing: 25-100mg/kg/day in divided doses every 6-12 hours
- Otitis media: 75-100mg/kg/day in divided doses every 6-12 hours
- Pharyngitis/tonsillitis: 25-50mg/kg/day in divided doses every 12 hours
Indications
- Uncomplicated urinary tract infections
- Skin and soft tissue infections
- Respiratory tract infections
- Otitis media
- Pharyngitis/tonsillitis
Mechanism of Action
- Inhibits bacterial cell wall synthesis
- Interferes with peptidoglycan layer formation
- Bactericidal activity
Contraindications
- Hypersensitivity to cefalexin or other cephalosporins
- History of severe hypersensitivity reactions to penicillins
Adverse Reactions
- Diarrhea
- Nausea
- Vomiting
- Abdominal pain
- Hypersensitivity reactions (rash, urticaria, anaphylaxis)
- Clostridioides difficile-associated diarrhea
Drug Interactions
- Probenecid: increases cefalexin levels
- Warfarin: increases risk of bleeding
- Metformin: increases risk of lactic acidosis
Curated Content: Needs Vetting Before Put to Clinical Use