Cephalexin Dosing for Uncomplicated Skin and Skin Structure Infections in Adults
For adults with uncomplicated skin and skin structure infections, the recommended dose of cephalexin is 500 mg orally four times daily (every 6 hours) for 7 days. 1, 2
Standard Dosing Regimen
- The FDA-approved adult dosage range for cephalexin is 1 to 4 g daily in divided doses 2
- For uncomplicated skin and skin structure infections specifically, 500 mg every 6 hours (2 g total daily dose) is the recommended regimen 1, 2
- An alternative dosing regimen of 500 mg every 12 hours (1 g total daily dose) may be used for less severe skin infections 2
- Duration of therapy is typically 7 days, depending on clinical response 1
Clinical Considerations
- Cephalexin is an oral first-generation cephalosporin with excellent activity against methicillin-susceptible Staphylococcus aureus (MSSA) and Streptococcus species, which are the most common pathogens in uncomplicated skin infections 1
- For patients with penicillin allergy (except those with immediate hypersensitivity reactions), cephalexin is an appropriate alternative 1
- In clinical trials, cephalexin has demonstrated similar efficacy to other antibiotics for skin infections, with clinical cure rates of approximately 85-91% 3, 4
Special Populations and Situations
- For more severe infections or those caused by less susceptible organisms, larger doses may be needed, up to 4 g daily 2
- If daily doses greater than 4 g are required, parenteral cephalosporins should be considered 2
- For patients with significant renal impairment, dose adjustment may be necessary 2
- For patients with MRSA risk factors, alternative antibiotics with MRSA coverage should be considered, as cephalexin is not effective against MRSA 1, 3
Monitoring and Follow-up
- Assess clinical response within 48-72 hours of initiating therapy 3
- If no improvement is seen or the infection worsens, consider obtaining cultures and modifying therapy 1
- Common adverse effects include diarrhea (4%), nausea, and headache 3
- Discontinuation due to adverse effects is relatively uncommon (approximately 4% of patients) 4
Alternative Regimens
- For patients unable to tolerate cephalexin, alternatives include:
Remember that appropriate dosing of cephalexin is essential for optimal clinical outcomes while minimizing adverse effects and the development of antimicrobial resistance.