What is the recommended dose and frequency of Fosfomycin (antibiotic) for the treatment of Urinary Tract Infection (UTI)?

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 American College of Physicians 1. This single dose is the complete treatment regimen for most uncomplicated UTIs and has been shown to be effective against common UTI pathogens, including E. coli and Enterococcus. The medication should be taken on an empty stomach, preferably in the evening before bedtime and after emptying the bladder. Patients should dissolve the powder completely in 3-4 ounces (90-120 mL) of cold water, stir well, and drink immediately.

Key Points to Consider

• Fosfomycin works by inhibiting bacterial cell wall synthesis and achieves high urinary concentrations that persist for 24-48 hours after a single dose, which is why one dose is usually sufficient 1.
• The American College of Physicians recommends short-course antibiotics, including fosfomycin as a single dose, for the treatment of uncomplicated bacterial cystitis in women 1.
• For complicated UTIs or in certain clinical situations, physicians may occasionally prescribe additional doses (typically every 2-3 days), but this is not the standard regimen.
• Patients should drink plenty of fluids while taking fosfomycin and should complete the full treatment even if symptoms improve quickly.

Administration and Dosage

• The recommended dose of fosfomycin is a single 3-gram oral dose, which is equivalent to one sachet of fosfomycin tromethamine powder dissolved in water 1.
• The medication should be taken on an empty stomach, preferably in the evening before bedtime and after emptying the bladder.
• Patients should dissolve the powder completely in 3-4 ounces (90-120 mL) of cold water, stir well, and drink immediately.

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 and frequency of Fosfomycin for the treatment of Urinary Tract Infection (UTI) is:

• One sachet of fosfomycin tromethamine granules for oral solution
• The dosage is for uncomplicated urinary tract infection (acute cystitis) in women 18 years of age and older
• The medication should be taken with water, after mixing the granules with water, and can be taken with or without food 2

From the Research

Recommended Dose and Frequency of Fosfomycin for UTI Treatment

• The recommended dose of fosfomycin for the treatment of urinary tract infections (UTIs) is a 3-g single dose of fosfomycin tromethamine 3.
• Fosfomycin is considered a first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females 3.
• A single dose of fosfomycin (300 mg) has been found to be effective in the treatment of uncomplicated lower urinary tract infection (UTI) in women 4.
• Single-dose fosfomycin presents a potentially useful and safe treatment option for the treatment of uncomplicated UTI in women and asymptomatic bacteriuria in pregnancy 4.

Comparison with Other Antibiotics

• Fosfomycin has been compared to nitrofurantoin in the treatment of uncomplicated UTI, with no significant differences in clinical and microbiological cure rates found within 4 weeks of treatment 4.
• The incidence of adverse events was found to be more in fosfomycin relative to the nitrofurantoin group 4.
• Fosfomycin trometamol and the 4-quinolones are considered promising agents for single-dose therapy of uncomplicated UTIs 5.

Treatment Guidelines

• Fosfomycin is considered a treatment option for UTIs due to AmpC- β-lactamase-producing Enterobacteriales, ESBLs-E coli, and ESBLs-Klebsiella pneumoniae 3.
• Fosfomycin is also considered a treatment option for UTIs caused by carbapenem-resistant Enterobacteriales (CRE) and multidrug-resistant (MDR)-Pseudomonas spp. 3.