What is the role of fosfomycin (Fosfomycin tromethamine) in treating uncomplicated urinary tract infections (UTIs) in males?

Fosfomycin in Urinary Tract Infections in Males

Fosfomycin is not recommended as a first-line treatment for urinary tract infections in males due to limited evidence supporting its efficacy in this population and the fact that male UTIs are generally considered complicated. 1, 2

Classification and Considerations for Male UTIs

Male UTIs are typically classified as complicated UTIs due to:

• Anatomical differences (longer urethra)
• Potential involvement of the prostate
• Higher likelihood of structural abnormalities
• Greater risk of treatment failure

Evidence-Based Treatment Recommendations

First-Line Options for Male UTIs

According to the European Association of Urology (EAU) 2024 guidelines and other authoritative sources, preferred treatments for male UTIs include:

• Amoxicillin-clavulanic acid (first-choice option) 1
• Nitrofurantoin (first-choice option) 1, 2
• Trimethoprim-sulfamethoxazole (first-choice option) 1, 2

Role of Fosfomycin in Male UTIs

While fosfomycin has several favorable properties:

• High urinary concentrations (706 ± 466 mcg/mL within 2-4 hours after dosing) 3
• Broad spectrum activity against common uropathogens 3
• Low resistance rates compared to other antibiotics 4
• Convenient single-dose administration 5

Its use in male UTIs is limited because:

1. Most clinical trials establishing fosfomycin's efficacy were conducted in women with uncomplicated UTIs 5
2. Male UTIs often involve deeper tissue infection requiring longer treatment duration
3. The single-dose regimen may be insufficient for male UTIs
4. Limited distribution to prostate tissue compared to other agents

Special Situations Where Fosfomycin May Be Considered

Fosfomycin might be considered in males with UTIs in specific scenarios:

1. Multidrug-resistant (MDR) organisms: When susceptibility testing shows resistance to first-line agents but sensitivity to fosfomycin 6

2. Intolerance to first-line agents: When patients cannot tolerate recommended first-line treatments 7

3. Lower UTI (cystitis) without prostate involvement: In this case, an extended regimen of fosfomycin may be considered:

   • 3g every 48-72 hours for a total of 3 doses 7
   • This extended regimen has shown 75-80% clinical success rates in complicated UTIs 8

Risk Factors for Treatment Failure with Fosfomycin

Studies have identified several factors associated with fosfomycin treatment failure in complicated UTIs:

• Male sex 8
• Urological abnormalities 8
• Non-E. coli infections 8
• Insufficient initial IV therapy before oral switch 8

Monitoring and Follow-up

When fosfomycin is used for male UTIs:

• Clinical improvement should be expected within 48-72 hours
• Follow-up urine cultures are recommended 1-2 weeks after completing therapy if symptoms persist 2
• Monitor for emergence of resistance, which has been reported in 14% of patients in follow-up cultures >30 days after treatment 8

Conclusion

While fosfomycin is an effective option for uncomplicated UTIs in women, its role in treating UTIs in males is limited. Standard first-line options like amoxicillin-clavulanic acid, nitrofurantoin, or trimethoprim-sulfamethoxazole should be preferred unless specific circumstances (resistance patterns, allergies) dictate otherwise.