Cephalexin Dosing for Skin Abrasion
For a skin abrasion, the recommended dose of cephalexin (Keflex) is 500 mg orally three times daily for adults. 1
Adult Dosing Recommendations
- Cephalexin 500 mg three times daily is the standard oral dose for skin and soft tissue infections including skin abrasions 1
- For more severe infections, the dose may be increased to 500 mg four times daily 1
- The FDA-approved adult dosage range is 1-4 g daily in divided doses, with the usual adult dose being 250 mg every 6 hours 2
- For skin and skin structure infections, 500 mg may be administered every 12 hours, though more frequent dosing is typically recommended for skin abrasions 2
Pediatric Dosing Recommendations
- For children, the recommended dosage is 25-50 mg/kg/day divided into 3-4 doses 2
- For skin and skin structure infections in children, the total daily dose may be divided and administered every 12 hours 2
- In severe infections, the pediatric dosage may be doubled 2
Duration of Therapy
- Treatment duration for uncomplicated skin infections is typically 7 days, depending on clinical response 1
- If the infection has not improved within 5 days, treatment should be extended 1
Clinical Considerations
- Cephalexin is effective against the most common pathogens causing skin infections, including Staphylococcus aureus (MSSA) and Streptococcus species 1
- Cephalexin has good activity against staphylococci and streptococci but misses Pasteurella multocida and anaerobes 1
- For simple skin abrasions without signs of significant infection, topical antimicrobial agents may be sufficient 1
Special Populations
- For patients with renal impairment (creatinine clearance <30 ml/min), dose reduction is required proportional to the reduced renal function 3
- Elderly patients may require dose adjustment based on renal function 3
Monitoring and Follow-up
- Assess clinical response within 3-5 days of initiating therapy 4
- If systemic signs of infection develop (temperature >38°C or <36°C, tachypnea >24 breaths/minute, tachycardia >90 beats/minute, or white blood cell count >12,000 or <400 cells/μL), consider broadening antimicrobial coverage 1
Potential Pitfalls and Caveats
- Cephalexin is not effective against MRSA; if MRSA is suspected or confirmed, alternative agents such as trimethoprim-sulfamethoxazole, doxycycline, or clindamycin should be considered 1
- Allergic cross-reactivity may occur in patients with penicillin allergy, although this is less common with cephalexin than with earlier generation cephalosporins 3
- Gastrointestinal side effects (diarrhea, nausea) are the most common adverse reactions 4
- Cephalexin is well absorbed from the gastrointestinal tract and excreted in high concentration in the urine, making it an excellent choice for uncomplicated skin infections 3, 5