Keflex (Cephalexin) Dosing for Soft Tissue Infections
For soft tissue infections, Keflex (cephalexin) should be administered at a dose of 500 mg orally four times daily for adults, with a total daily dose of 1-4 grams divided throughout the day. 1
Adult Dosing Recommendations
- For mild to moderate skin and soft tissue infections, the standard adult dose is 500 mg orally every 6 hours (four times daily) 2, 1
- Alternative dosing regimen: 500 mg orally every 12 hours (twice daily) may be considered for skin and skin structure infections, though the four-times-daily regimen is preferred for better coverage 1, 3
- For more severe infections, doses up to 4 grams daily in divided doses may be required 1
- The typical duration of therapy for skin and soft tissue infections is 7 days, but may be extended if the infection has not improved within this time period 2
Pediatric Dosing Recommendations
- For children, the recommended dosage is 25-50 mg/kg/day divided into four doses 1
- For skin and skin structure infections in pediatric patients over 1 year of age, the total daily dose may be divided and administered every 12 hours 1
- In severe infections, the pediatric dosage may be doubled 1
Clinical Considerations
- Cephalexin provides good coverage against methicillin-susceptible Staphylococcus aureus (MSSA) and streptococci, which are common pathogens in soft tissue infections 2
- For patients with impaired renal function (creatinine clearance <30 mL/min), dose reduction is required proportional to the reduced kidney function 4
- Cephalexin is not effective against methicillin-resistant Staphylococcus aureus (MRSA); alternative agents should be considered if MRSA is suspected 2
Special Situations
- For recurrent soft tissue infections, obtain cultures before starting antibiotics 2
- For soft tissue infections associated with animal or human bites, amoxicillin-clavulanate is preferred over cephalexin due to better coverage against Pasteurella multocida and anaerobes 2
- For diabetic foot infections or other complicated soft tissue infections, broader spectrum antibiotics may be necessary 2
Efficacy and Safety
- Clinical studies have demonstrated high efficacy rates (>90%) for cephalexin in the treatment of skin and soft tissue infections 5, 6
- Cephalexin has been shown to be non-inferior to parenteral options for uncomplicated mild to moderate skin and soft tissue infections 7
- Common adverse effects include gastrointestinal disturbances and, rarely, hypersensitivity reactions 5, 6
Important Caveats
- Cephalexin should not be used in patients with known hypersensitivity to cephalosporins 1
- For patients with immediate hypersensitivity reactions to penicillins, cross-reactivity with cephalexin is possible, and alternative agents should be considered 2
- If no clinical improvement is observed after 72 hours of therapy, reassess the diagnosis and consider alternative antibiotics 7
Remember that cephalexin is administered orally and is well-absorbed from the gastrointestinal tract, with excellent distribution to tissues involved in skin and soft tissue infections 4.