Single-Dose UTI Medication
Fosfomycin tromethamine 3 grams orally as a single dose is the medication for uncomplicated urinary tract infections. 1, 2
Dosing and Administration
- The standard dose is one 3-gram sachet of fosfomycin tromethamine granules mixed with water, taken as a single oral dose 2
- The medication must be mixed with water before ingestion and should never be taken in dry form 2
- It can be taken with or without food 2
- This single-dose regimen provides therapeutic urinary concentrations for 24-48 hours 1
Guideline Recommendations
- The American Urological Association recommends fosfomycin as one of three first-line therapies for uncomplicated UTIs with a strong recommendation (Grade B evidence) 1
- The European Association of Urology recommends fosfomycin trometamol 3g single dose as a first-line treatment option for uncomplicated cystitis in women 1, 3
- For vancomycin-resistant Enterococcus (VRE) causing uncomplicated UTIs, the same single 3-gram oral dose is recommended 4
Clinical Efficacy
- Clinical recovery rates of 88.9% and bacteriological eradication rates of 94.9% have been achieved with single-dose fosfomycin 5
- Clinical efficacy is comparable to other first-line agents including nitrofurantoin, despite somewhat lower bacterial efficacy 1
- The convenience of single-dose administration improves adherence compared to 3-7 day regimens 1
Important Limitations
- Fosfomycin is recommended ONLY for uncomplicated cystitis in women and should NOT be used for pyelonephritis, complicated UTIs, or routinely in men due to insufficient efficacy data 1
- It is not recommended for asymptomatic bacteriuria except in pregnant women and before urological procedures breaching the mucosa 1
Safety Profile
- The most common adverse effects are gastrointestinal disturbances including diarrhea, nausea, and vomiting, which are typically mild and self-limiting 1, 6
- Fosfomycin has minimal propensity for collateral damage to intestinal flora compared to other antibiotics 1
- It is safe in pregnancy and recommended for asymptomatic bacteriuria in pregnant women 1
Clinical Pearls
- Fosfomycin has minimal cross-resistance with other antibacterial agents due to its unique chemical structure and site of action 6
- It is particularly active against E. coli and has activity against multidrug-resistant pathogens including ESBL-producing organisms, VRE, and MRSA 1
- If symptoms do not resolve by the end of treatment or recur within 2 weeks, obtain urine culture and antimicrobial susceptibility testing 1