Fosfomycin for Uncomplicated Urinary Tract Infections
Fosfomycin trometamol (3g single dose) is recommended as a first-line treatment option for uncomplicated urinary tract infections (acute cystitis) in women due to its convenience, efficacy, and minimal impact on gut flora. 1, 2
Indications and Efficacy
- FDA-approved specifically for uncomplicated UTIs (acute cystitis) in women due to susceptible strains of Escherichia coli and Enterococcus faecalis 2
- Clinical efficacy rate of approximately 91% and microbiological efficacy rate of 80% 3
- Recent studies show high clinical recovery (88.9%) and bacteriological eradication rates (94.9%) 4
- Particularly effective against E. coli with susceptibility rates of 95.9-96.1% for both non-ESBL and ESBL-producing strains 5
Dosage and Administration
- Single 3g sachet dissolved in water 2
- Can be taken with or without food 2
- No need for multiple doses, improving patient compliance 1
Advantages of Fosfomycin
- Convenient single-dose regimen 3, 1
- Minimal propensity for collateral damage to gut flora 3, 1
- Maintains activity against many drug-resistant pathogens, including ESBL-producing organisms 6, 7
- Excellent option when other oral agents with in vitro activity are not available 3
Limitations and Considerations
- Not indicated for pyelonephritis or perinephric abscess 2
- Slightly lower bacterial efficacy compared to other first-line agents 3
- If symptoms persist or bacteriuria recurs after treatment, alternative agents should be selected 2
- Common side effects include diarrhea, nausea, and headache, though generally mild (reported in only 4.3% of patients) 3, 4
Alternative First-Line Options
When fosfomycin is not appropriate, consider:
- Nitrofurantoin (100mg twice daily for 5 days) - comparable efficacy to fosfomycin with clinical and microbiological cure rates showing no significant differences 8
- Trimethoprim-sulfamethoxazole (160/800mg twice daily for 3 days) - only if local resistance is <20% 1
Special Populations
- Fosfomycin is an option for pregnant women with uncomplicated UTIs 1
- For male UTIs, which are considered complicated by definition, fosfomycin is not the first choice as longer treatment durations (7-14 days) are typically recommended 1
When to Use Alternative Therapy
- If local resistance patterns show poor susceptibility to fosfomycin
- For complicated UTIs including pyelonephritis
- If symptoms persist after treatment with fosfomycin
- For patients with recurrent infections after fosfomycin therapy
Fosfomycin's role in treating UTIs has increased in importance as antimicrobial resistance rises, making it a valuable option in the current antimicrobial stewardship landscape 6.