Overview
Cefaclor is a second-generation cephalosporin antibiotic used to treat various bacterial infections including respiratory tract infections, otitis media, skin infections, and urinary tract infections. It works by inhibiting bacterial cell wall synthesis and is administered orally. The drug requires careful consideration in patients with penicillin allergies due to potential cross-reactivity.
Mechanism of Action
Cefaclor is a bactericidal cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking and leading to cell lysis and death.
Indications
- Lower respiratory tract infections (pneumonia, bronchitis) caused by Streptococcus pneumoniae, Haemophilus influenzae, and Streptococcus pyogenes
- Otitis media caused by Streptococcus pneumoniae, Haemophilus influenzae, and Streptococcus pyogenes
- Pharyngitis and tonsillitis caused by Streptococcus pyogenes
- Urinary tract infections (cystitis, pyelonephritis) caused by Escherichia coli, Proteus mirabilis, Klebsiella species, and coagulase-negative staphylococci
- Skin and skin structure infections caused by Staphylococcus aureus and Streptococcus pyogenes
Common Doses
- 250 mg
- 500 mg
- 125 mg/5 mL oral suspension
- 250 mg/5 mL oral suspension
Dosage
Adults: 250 mg every 8 hours; may increase to 500 mg every 8 hours for severe infections. Pediatric patients: 20 mg/kg/day divided every 8 hours; may increase to 40 mg/kg/day for severe infections or otitis media (maximum 1 g/day). For β-hemolytic streptococcal infections, continue treatment for at least 10 days.
Contraindications
- Known hypersensitivity to cefaclor or other cephalosporin antibiotics
Side Effects
- Hypersensitivity reactions (1.5%): morbilliform eruptions, pruritus, urticaria
- Serum-sickness-like reactions: erythema multiforme, rashes with arthritis/arthralgia, fever
- Gastrointestinal (2.5%): diarrhea, nausea, vomiting
- Hepatic: transient hepatitis, cholestatic jaundice
- Hematologic: eosinophilia, thrombocytopenia, reversible neutropenia
- Renal: reversible interstitial nephritis
- CNS: dizziness, headache, nervousness, insomnia
Interactions
- Warfarin (Coumadin): may increase prothrombin time and bleeding risk
- Probenecid: may increase cefaclor serum concentrations
Counseling Points
- Complete full course of therapy even if symptoms improve
- Take with food if gastrointestinal upset occurs
- Report any rash, joint pain, diarrhea, or signs of allergic reaction immediately
- Inform healthcare provider of any penicillin allergy history
- Space doses evenly throughout the day
- Shake oral suspension well before use