What is the recommended dosage and duration of Keflex (Cephalexin) for outpatient wound care?

Keflex (Cephalexin) Dosage for Outpatient Wound Infections

For outpatient wound infections, Keflex (cephalexin) should be prescribed at a dosage of 500 mg four times daily for 5-6 days. This dosage is recommended by the Infectious Diseases Society of America guidelines for skin and soft tissue infections 1.

Dosing Recommendations

Adult Dosing

• Standard dose: 500 mg orally four times daily 2
• Alternative dosing: 500 mg every 12 hours for less severe infections 3
• Duration: 5-6 days is as effective as 10 days if clinical improvement occurs by day 5 1
• Maximum daily dose: Should not exceed 4 g per day 3

Pediatric Dosing

• Standard dose: 25-50 mg/kg/day divided into 4 doses 3
• For skin infections: Higher dosing of 75-100 mg/kg/day in 4 divided doses may be required 1
• Duration: Same as adults (5-6 days) with reassessment

Clinical Decision Algorithm

1. Assess wound severity:

   • For non-purulent, mild to moderate wound infections → Cephalexin 500 mg four times daily
   • For purulent wounds or suspected MRSA → Consider alternative antibiotics (clindamycin, TMP-SMX)

2. Consider patient factors:

   • Penicillin allergy → Use clindamycin 300-450 mg three times daily instead 2, 1
   • Renal impairment (CrCl <30 ml/min) → Reduce dosage proportionally 4

3. Reassess within 48-72 hours:

   • If improving → Complete 5-6 day course
   • If not improving → Consider MRSA coverage or alternative diagnosis 1

Evidence Strength and Considerations

The 5-6 day duration recommendation is based on high-quality evidence from the Infectious Diseases Society of America, showing that shorter courses are as effective as traditional 10-day courses when clinical improvement occurs 1. This shorter duration helps improve compliance while reducing antibiotic exposure.

Research shows that cephalexin administered twice daily may be as effective as four times daily dosing for skin infections, with both regimens showing >97% effectiveness 5. However, the IDSA guidelines still recommend the four-times-daily dosing for optimal pharmacokinetics 2.

Common Pitfalls to Avoid

• Pitfall #1: Treating for too long. Evidence shows 5-6 days is sufficient for most uncomplicated wound infections if clinical improvement occurs 1.
• Pitfall #2: Not reassessing within 48-72 hours. Early reassessment allows for timely adjustment if treatment is failing 1.
• Pitfall #3: Using cephalexin for suspected MRSA infections. Cephalexin lacks MRSA coverage; consider clindamycin or TMP-SMX if MRSA is suspected 2.
• Pitfall #4: Overlooking patient adherence challenges with four-times-daily dosing. While twice-daily dosing may be considered for adherence issues, the standard recommendation remains four times daily 5.

For patients with recurrent infections, addressing underlying predisposing conditions (edema, obesity, eczema) is crucial for preventing future episodes 1.