From the FDA Drug Label
For the following infections, a dosage of 500 mg may be administered every 12 hours: streptococcal pharyngitis, skin and skin structure infections, and uncomplicated cystitis in patients over 15 years of age. The recommended dosage of Cephalexin (Keflex) for the treatment of cellulitis, which is a type of skin and skin structure infection, is 500 mg every 12 hours 1.
- The dosage may be adjusted based on the severity of the infection.
- For more severe infections, larger doses may be needed.
- If daily doses of cephalexin greater than 4 g are required, parenteral cephalosporins should be considered.
From the Research
For the treatment of cellulitis, the recommended dosage of Cephalexin (Keflex) is 1000 mg taken orally four times daily for 7 days, as this high-dose regimen has been shown to have fewer treatment failures compared to the standard dose 2.
Key Considerations
- The dosage may vary depending on the severity of the infection and the patient's clinical response.
- Children may receive 25-50 mg/kg/day divided into four doses.
- It is essential to take the full course of antibiotics even if symptoms improve before completion.
- Common side effects include diarrhea, nausea, and rash.
- If you have a penicillin allergy, inform your doctor as there is potential cross-reactivity.
Important Notes
- Drink plenty of fluids while taking Keflex, and elevate the affected area when possible to reduce swelling.
- Seek immediate medical attention if the infection worsens, spreads, or if you develop fever, increasing pain, or red streaks extending from the infected area.
- The use of cephalexin plus trimethoprim-sulfamethoxazole compared to cephalexin alone did not result in higher rates of clinical resolution of cellulitis in the per-protocol analysis, but further research may be needed 3.
- A study comparing short-course (5 days) and standard (10 days) treatment for uncomplicated cellulitis found no significant difference in clinical outcome between the two courses of therapy 4.
- The addition of an oral anti-inflammatory agent to antibiotic treatment has been shown to significantly shorten the time to regression of inflammation and complete resolution of cellulitis 5.