What is the dose of cephalexin (Cephalexin) for surgical site infections?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: July 2, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

The recommended dose of cephalexin for surgical site infections is 500 mg orally every 6 hours for adults with normal renal function. This dosage is based on the guidelines for the diagnosis and management of skin and soft tissue infections, as outlined in the 2014 update by the Infectious Diseases Society of America 1.

Key Considerations

  • The duration of treatment usually ranges from 7 to 14 days, depending on the severity of the infection and clinical response.
  • For patients with renal impairment, dose adjustment is necessary: for creatinine clearance 10-50 mL/min, reduce to 500 mg every 8-12 hours; for clearance less than 10 mL/min, reduce to 250-500 mg every 12-24 hours.
  • Children may receive 25-50 mg/kg/day divided into four equal doses, as specified in the guidelines 1.

Mechanism and Efficacy

  • Cephalexin is effective against many gram-positive bacteria commonly causing surgical site infections, including Staphylococcus aureus (non-MRSA) and streptococci.
  • It works by inhibiting bacterial cell wall synthesis.

Administration and Side Effects

  • Patients should complete the full course of antibiotics even if symptoms improve before completion.
  • Common side effects include gastrointestinal disturbances, and it should be taken with food if stomach upset occurs.
  • Allergic reactions are possible, especially in patients with penicillin allergies due to cross-reactivity.

Guideline Recommendations

  • The guidelines also recommend other antibiotics such as oxacillin, nafcillin, cefazolin, and vancomycin for surgical site infections, depending on the specific circumstances and patient factors 1.

From the FDA Drug Label

The usual adult dose is 250 mg every 6 hours For the following infections, a dosage of 500 mg may be administered every 12 hours: streptococcal pharyngitis, skin and skin structure infections, and uncomplicated cystitis in patients over 15 years of age.

The dose of cephalexin for surgical site infections is not explicitly stated in the drug label. However, for skin and skin structure infections, a dosage of 500 mg may be administered every 12 hours.

  • Key points:
    • Adult dose: 250 mg every 6 hours or 500 mg every 12 hours for certain infections
    • Infection type: skin and skin structure infections
    • Dosage: 500 mg every 12 hours 2

From the Research

Dose of Cephalexin for Surgical Site Infections

  • The dose of cephalexin for surgical site infections is not explicitly stated in the provided studies, but we can look at the doses used in similar contexts:
    • A study from 2012 3 used oral Cephalexin 500 mg qid (four times a day) for prophylaxis treatment in patients with simple traumatic contaminated wounds or lacerations.
    • Another study from 1998 4 compared cefdinir and cephalexin for the treatment of skin and skin-structure infections, with cephalexin being administered at a dose of 500 mg QID (four times a day) for 10 days.
  • It's worth noting that the dose of cephalexin may vary depending on the specific infection being treated, as well as the patient's renal function and other factors:
    • A study from 1983 5 noted that patients with creatinine clearances less than 30 ml/min require a reduction in cephalexin dosage, which should be proportional to the reduced function.
    • The same study also mentioned that children may need higher doses per kilogram than those used in treating adults due to their greater body water turnover.
  • In general, the dose of cephalexin for surgical site infections would likely be similar to that used for other types of skin and soft tissue infections, but the specific dose and duration of treatment should be determined by a healthcare professional based on the individual patient's needs and circumstances.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.