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 dose of Keflex (Cephalexin) for treating cellulitis is 500 mg every 12 hours 1.
- The dose 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
The recommended dose of Keflex (cephalexin) for treating cellulitis 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 of 500 mg four times daily, although with a higher proportion of minor adverse effects 2.
Key Considerations
- The dosage may need to be adjusted based on the patient's renal function and other comorbidities.
- Patients should be advised to complete the entire prescribed course of antibiotics, even if symptoms improve before finishing the medication.
- Keflex can be taken with or without food, but taking it with food may help alleviate stomach upset.
- Adequate hydration should be maintained throughout treatment to help prevent kidney damage.
Efficacy and Safety
- The high-dose cephalexin regimen has been shown to be effective in treating cellulitis, with a lower treatment failure rate compared to the standard dose 2.
- However, the high-dose regimen was also associated with a higher proportion of minor adverse effects, such as gastrointestinal upset.
- Patients with a history of kidney disease or penicillin allergy should inform their healthcare provider before starting treatment, as dosage adjustments may be necessary.
Comparison to Other Antibiotics
- Other studies have compared the efficacy of cephalexin to other antibiotics, such as cefdinir and trimethoprim-sulfamethoxazole, but the results are mixed and do not provide a clear alternative to cephalexin for the treatment of cellulitis 3, 4, 5.
- A study from 2000 found that cephalexin had a higher therapeutic failure rate compared to other antibiotics, but this study is outdated and may not reflect current treatment practices 6.