FDA Approves Fosfomycin Tromethamine (fosfomycin tromethamine) for Uncomplicated Urinary Tract Infections in Women

Not reported in label.

Fosfomycin tromethamine granules for oral solution is indicated only for the treatment of uncomplicated urinary tract infections (acute cystitis) in women due to susceptible strains of Escherichia coli and Enterococcus faecalis. It is not indicated for the treatment of pyelonephritis or perinephric abscess. The patient population in clinical studies consisted of women with symptoms and signs of acute cystitis of less than 4 days duration, no manifestations of upper tract infection, no history of recurrent urinary tract infections, no known structural abnormalities, no clinical or laboratory evidence of hepatic dysfunction, and no known or suspected CNS disorders.

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. It may be taken with or without food. Fosfomycin tromethamine granules for oral solution should not be taken in its dry form and must be mixed with water before ingesting.

In controlled, double-blind studies of acute cystitis, a single-dose of fosfomycin tromethamine was compared to other oral antibiotics. Microbiologic eradication rates 5-11 days post-therapy were: fosfomycin 630/771 (82%), ciprofloxacin 219/222 (98%), trimethoprim/sulfamethoxazole 194/197 (98%), and nitrofurantoin 180/238 (76%). Fosfomycin was inferior to ciprofloxacin and trimethoprim/sulfamethoxazole but equivalent to nitrofurantoin based on microbiologic eradication rates. For E. coli, fosfomycin had a rate of 509/644 (79%), and for E. faecalis, 10/10 (100%). Clinical success rates 5-11 days post-therapy were: fosfomycin 591/771 (77%), ciprofloxacin 219/222 (98%), trimethoprim/sulfamethoxazole 194/197 (98%), and nitrofurantoin 180/238 (76%). Adverse events reported in >1% of the fosfomycin-treated population included diarrhea (9.0%), vaginitis (5.5%), nausea (4.1%), headache (3.9%), dizziness (1.3%), asthenia (1.1%), and dyspepsia (1.1%).

Clostridium difficile associated diarrhea (CDAD) has been reported with use of fosfomycin tromethamine granules for oral solution and may range from mild diarrhea to fatal colitis. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Fosfomycin tromethamine granules for oral solution is contraindicated in patients with known hypersensitivity to the drug.

Fosfomycin tromethamine granules for oral solution is indicated for uncomplicated urinary tract infections (acute cystitis) in women due to susceptible E. coli and E. faecalis. It offers a single-dose regimen, which may be advantageous for adherence. In clinical trials, it showed lower efficacy compared to ciprofloxacin and trimethoprim/sulfamethoxazole but was equivalent to nitrofurantoin. It should not be used for pyelonephritis or perinephric abscess, and other agents should be selected if bacteriuria persists or reappears.