From the Guidelines
Fosfomycin should be administered as a single 3-gram oral dose for the treatment of uncomplicated urinary tract infections (UTIs) in adults, as recommended by the IDSA/European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guideline 1. This one-time dose is the complete treatment regimen for most uncomplicated UTIs in adults. The medication should be taken with water on an empty stomach, preferably in the evening before bedtime after emptying the bladder.
- The powder should be dissolved in 3-4 ounces (90-120 mL) of cold water, stirred well, and consumed immediately.
- Fosfomycin works by inhibiting bacterial cell wall synthesis and is effective against many common UTI pathogens, including E. coli and Enterococcus.
- It achieves high concentrations in the urinary tract and maintains therapeutic levels for 24-48 hours after a single dose.
- Patients should be advised that symptoms may not resolve immediately but should improve within 2-3 days.
- If symptoms persist beyond 3 days, they should contact their healthcare provider.
- Fosfomycin is generally well-tolerated, with diarrhea, headache, and nausea being the most common side effects, as noted in the guidelines 1.
From the FDA Drug Label
The recommended dosage for women 18 years of age and older for uncomplicated urinary tract infection (acute cystitis) is one sachet of fosfomycin tromethamine granules for oral solution. The recommended dose of Fosfomycin for a UTI is one sachet of fosfomycin tromethamine granules for oral solution, to be taken with water, for women 18 years of age and older with uncomplicated urinary tract infection (acute cystitis) 2.
From the Research
Fosfomycin Dose for UTI
- The recommended dose of fosfomycin for the treatment of urinary tract infections (UTIs) is a 3-g single dose of fosfomycin tromethamine 3.
- A systematic review and meta-analysis found that a single dose of 300mg oral fosfomycin was effective in the treatment of uncomplicated lower urinary tract infection (UTI) in women, with no significant differences in clinical and microbiological cure rates compared to nitrofurantoin 4.
- Fosfomycin trometamol is considered a promising agent for single-dose therapy of uncomplicated UTIs, along with trimethoprim or co-trimoxazole and the 4-quinolones 5.
- Alternative first-line agents for the treatment of acute uncomplicated UTI include fosfomycin, in addition to fluoroquinolones, nitrofurantoin, and trimethoprim-sulfamethoxazole 6.
- A single oral dose of an antimicrobial agent, including fosfomycin, is as effective as a conventional 3-day course for the treatment of uncomplicated lower urinary tract infections 7.