Praxis Medical Insights

Est. 2024 • Clinical Guidelines Distilled

Made possible by volunteer editors from the University of Calgary & University of Alberta

Last Updated: 8/24/2025

Cephalexin Dosage and Clinical Applications

Skin and Soft Tissue Infections

  • For impetigo, the Infectious Diseases Society of America recommends a dosage of 250 mg four times daily for adults or 25-50 mg/kg/day in 3-4 divided doses for children 1, 2
  • For surgical site infections, a dosage of 500 mg every 6 hours orally is effective 3, 4
  • For methicillin-susceptible S. aureus skin infections, a dosage of 500 mg four times daily orally is recommended 1, 5

Duration of Therapy

  • For skin and soft tissue infections, the typical duration of therapy is 7 days, depending on clinical response, as recommended by the Infectious Diseases Society of America 2

Important Limitations

  • Cephalexin is not effective against methicillin-resistant Staphylococcus aureus, as stated by the Infectious Diseases Society of America 1, 2