What is the recommended dosing for cephalexin (Keflex) in the treatment of wound infections?

Cephalexin Dosing for Wound Infections

For standard wound infections in adults, cephalexin should be dosed at 500 mg orally four times daily for 7-10 days. 1, 2

Adult Dosing Regimen

• First-line dosing: 500 mg orally every 6 hours (2 g total daily dose)
• Duration: 7-10 days for most wound infections
• Alternative dosing: For less severe skin infections, 500 mg every 12 hours may be sufficient 2
• Maximum daily dose: 4 g (if higher doses needed, consider parenteral therapy) 2

Pediatric Dosing Regimen

• Standard dose: 25-50 mg/kg/day divided into 4 doses 2
• For skin infections: Can be divided into twice daily dosing 2
• Severe infections: May double the dosage to 50-100 mg/kg/day 2

Clinical Considerations

Type of Wound Infection

• Simple wound infections: 500 mg four times daily for 7-10 days 1
• Infected surgical sites: 500 mg four times daily 1
• Animal or human bites: Cephalexin alone is NOT recommended (poor activity against Pasteurella multocida); use amoxicillin-clavulanate instead 1

Special Populations

• Renal impairment: Dose reduction required for creatinine clearance <30 mL/min 3
• Severe infections: May require higher doses within the 1-4 g daily range 2

Efficacy and Alternatives

Cephalexin is effective against most common wound pathogens including:

• Methicillin-susceptible Staphylococcus aureus (MSSA)
• Streptococcus species
• Some gram-negative organisms

For MRSA infections, alternative agents should be considered:

• Trimethoprim-sulfamethoxazole
• Clindamycin
• Doxycycline
• Linezolid or vancomycin for severe infections 1

Important Clinical Pearls

1. Start empiric therapy promptly for hand wounds and puncture wounds 4
2. Obtain cultures in patients with malignancy, neutropenia, severe immunodeficiency, immersion injuries, or animal bites 1
3. Reassess after 48-72 hours - if no improvement, consider MRSA or other resistant organisms 4
4. Wound care is essential - proper cleaning, debridement if needed, and appropriate dressing changes are as important as antibiotic therapy 1
5. Short-course therapy (2 days) may be as effective as 5-day regimens for simple contaminated traumatic wounds after proper wound care 5

Common Pitfalls to Avoid

1. Using cephalexin for animal bites - poor activity against Pasteurella multocida; use amoxicillin-clavulanate instead 1
2. Inadequate dosing - underdosing can lead to treatment failure and resistance
3. Overlooking surgical drainage for abscesses - antibiotics alone are often insufficient 1
4. Prolonged therapy without clear indication - most uncomplicated wound infections respond to 7-10 days of therapy 1
5. Failing to consider MRSA in non-responsive infections - particularly important in recurrent skin infections 1

Cephalexin remains a cost-effective first-line option for most uncomplicated wound infections, with excellent oral bioavailability and a favorable safety profile 3.