From the Guidelines
Keflex (Cephalexin) is not the first-line treatment for Urinary Tract Infections (UTIs) due to its inferior efficacy and higher propensity for adverse effects compared to other recommended agents. According to the 2010 update by the Infectious Diseases Society of America and the European Society for Micrology and Infectious Diseases 1, beta-lactam agents, including cephalexin, are less well studied and may be appropriate in certain settings, but have inferior efficacy and more adverse effects compared to other UTI antimicrobials.
Some key points to consider when treating UTIs include:
- Nitrofurantoin monohydrate/macrocrystals and trimethoprim-sulfamethoxazole are recommended as first-line treatments due to their efficacy and minimal resistance 1
- Fosfomycin trometamol and pivmecillinam are also appropriate choices for therapy in certain regions due to minimal resistance and propensity for collateral damage 1
- Fluoroquinolones, such as ofloxacin, ciprofloxacin, and levofloxacin, are highly efficacious but should be reserved for important uses other than acute cystitis due to their propensity for collateral damage 1
If Keflex is prescribed for a UTI, the typical dosage for adults is 250-500 mg taken orally every 6 hours, or 500-1000 mg every 12 hours, for 7-14 days depending on infection severity 1. Patients should complete the entire prescribed course even if symptoms improve before finishing, and common side effects include diarrhea, nausea, and skin rashes. Those with penicillin allergies should use caution as there is potential for cross-reactivity. Drinking plenty of water during treatment helps flush bacteria from the urinary system and may reduce symptoms. If symptoms don't improve within 48-72 hours of starting treatment, patients should contact their healthcare provider as a different antibiotic may be needed.
From the FDA Drug Label
Genitourinary tract infections, including acute prostatitis, caused by Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae Keflex (Cephalexin) is effective for treating certain types of Urinary Tract Infections (UTIs) caused by susceptible strains of microorganisms, including:
- Escherichia coli
- Proteus mirabilis
- Klebsiella pneumoniae However, it is essential to note that culture and susceptibility tests should be initiated prior to and during therapy to ensure the bacteria are susceptible to cephalexin 2.
From the Research
Effectiveness of Keflex for UTI
- Keflex (Cephalexin) is a second-line option for treating Urinary Tract Infections (UTIs) 3.
- It is effective against certain bacteria that cause UTIs, but its use may be limited by resistance patterns in certain regions 4.
- A study found that short courses of twice-daily cephalexin appear to be a safe and effective option for the empiric treatment of uncomplicated UTIs, with a clinical success rate of 81.1% 5.
- However, another study found that cephalexin had a high resistance rate in a U.S.-Mexico border region, making it a less ideal empiric antibiotic for treatment of outpatient UTI in that area 4.
Recommended Treatment Options for UTI
- First-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis includes nitrofurantoin, fosfomycin tromethamine, or pivmecillinam 3.
- Second-line options include oral cephalosporins such as cephalexin or cefixime, fluoroquinolones, and β-lactams like amoxicillin-clavulanate 3.
- The choice of antibiotic should be guided by local susceptibility patterns and resistance rates 3, 4.
Considerations for Using Keflex
- Keflex may not be effective against all types of bacteria that cause UTIs, particularly those with high resistance rates 4.
- Its use should be tailored to local resistance patterns and guided by culture and sensitivity results when possible 3, 4.
- Alternative antibiotics such as nitrofurantoin, amoxicillin-clavulanate, or second- and third-generation cephalosporins may be more effective in certain regions or cases 5, 4.