From the FDA Drug Label
For the following infections, a dosage of 500 mg may be administered every 12 hours: ... and uncomplicated cystitis in patients over 15 years of age. Cystitis therapy should be continued for 7 to 14 days. The recommended dosing of Cephalexin for Urinary Tract Infection (UTI), specifically uncomplicated cystitis, is 500 mg every 12 hours for patients over 15 years of age, and therapy should be continued for 7 to 14 days 1.
From the Research
For uncomplicated urinary tract infections (UTIs) in adults, the recommended dosing of cephalexin is 500 mg orally every 12 hours for 5-7 days, as supported by the most recent study 2.
Key Considerations
- The study published in 2023 2 found that twice-daily cephalexin was a safe and effective option for the empiric treatment of uncomplicated UTIs, with 81.1% of patients achieving clinical success.
- Cephalexin works by inhibiting bacterial cell wall synthesis, making it effective against many common UTI-causing organisms, particularly gram-positive bacteria and some gram-negative bacteria including Escherichia coli.
- However, increasing resistance patterns may limit its effectiveness in some cases, and culture results should guide therapy when available.
Important Notes
- Patients should complete the entire prescribed course even if symptoms improve before finishing.
- Adequate hydration is important during treatment to help flush bacteria from the urinary tract.
- Cephalexin should be taken with food if stomach upset occurs, though it can be taken without food.
Comparison with Other Studies
- Other studies, such as those published in 2020 3 and 2014 4, recommend different first-line antibiotics for uncomplicated UTIs, such as nitrofurantoin, fosfomycin, and trimethoprim-sulfamethoxazole.
- However, the 2023 study 2 provides the most recent and highest-quality evidence for the use of cephalexin in treating uncomplicated UTIs.