Cephalexin Dosing for Soft Tissue Infections

Pediatric and Adult Dosing Regimens

• The IDSA guidelines recommend cephalexin at 75-100 mg/kg/day divided into 3-4 doses for pediatric patients with methicillin-susceptible Staphylococcus aureus infections, which translates to the 500 mg four times daily regimen for adults in clinical practice 1, 2, 3

Microbiological Coverage and Critical Pitfalls to Avoid

• Cephalexin provides excellent activity against methicillin-susceptible Staphylococcus aureus and Streptococcus species, but is not effective against MRSA, Pasteurella multocida, and most anaerobes 2, 3
• If MRSA is suspected, cephalexin is inadequate and alternative agents such as trimethoprim-sulfamethoxazole, doxycycline, or clindamycin should be used instead 2, 3
• Patients with immediate hypersensitivity reactions to penicillin should avoid cephalexin due to potential cross-reactivity, but for non-immediate reactions, cephalexin remains an appropriate alternative 2, 3