FDA Approves Fosfomycin Tromethamine (fosfomycin tromethamine) for Uncomplicated Urinary Tract Infections in WomenFDA approves new single-dose antibiotic for treating bladder infections in women

FDA Published April 14, 2026 DOI ↗ Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

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Key Takeaway

Consider fosfomycin tromethamine for single-dose treatment of acute cystitis in women with susceptible pathogens.

The FDA has approved fosfomycin tromethamine granules for oral solution for the treatment of uncomplicated urinary tract infections (acute cystitis) in women caused by susceptible strains of Escherichia coli and Enterococcus faecalis. This approval provides a single-dose oral antibiotic option for a common infection, which may enhance patient adherence compared to multi-day regimens. The drug is not indicated for pyelonephritis or perinephric abscess, and clinicians should select other agents if bacteriuria persists or reappears after treatment. Clinical trial data show fosfomycin tromethamine had a microbiologic eradication rate of 82% 5-11 days post-therapy, though it was inferior to ciprofloxacin and trimethoprim/sulfamethoxazole in comparative studies. Adverse events include diarrhea, vaginitis, and nausea, with warnings for Clostridium difficile-associated diarrhea. This approval adds to the armamentarium for managing acute cystitis, particularly in cases where susceptibility aligns and single-dose therapy is preferred.

＋ Clinical Details (Mechanism · Dosing · Trial Data · Warnings)

Mechanism of Action

Not reported in label.

Indication & Patient Population

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.

Dosing & Administration

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.

Key Clinical Trial Data

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%).

Warnings & Contraindications

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.

Place in Therapy

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.

The U.S. Food and Drug Administration has approved a new antibiotic called fosfomycin tromethamine for treating uncomplicated urinary tract infections, commonly known as bladder infections. This medication is specifically for women with infections caused by certain bacteria. It comes as granules that are mixed with water and taken as a single oral dose, which may be more convenient than antibiotics that require multiple doses over several days.

This approval means doctors now have another treatment option for these common infections. The single-dose approach could help patients complete their full course of treatment more easily. However, it's important to understand that this medication is only for simple bladder infections and not for more serious kidney infections.

Clinical studies showed this antibiotic was effective against the bacteria that cause most bladder infections. Like all medications, it can have side effects including diarrhea, nausea, and vaginal infections. There's also a warning about a serious type of diarrhea that can occur with antibiotic use.

If you think you might have a bladder infection, the most important thing is to talk with your doctor. They can determine if this new treatment option is appropriate for your specific situation and help you understand the benefits and risks.

What this means for you:

New one-dose antibiotic option for bladder infections, but always consult your doctor first.

Study Details

Study typeFda approval

PublishedApr 2026

View Original Abstract ↓

INDICATIONS AND USAGE 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 . Fosfomycin tromethamine granules for oral solution is not indicated for the treatment of pyelonephritis or perinephric abscess. If persistence or reappearance of bacteriuria occurs after treatment with fosfomycin tromethamine granules for oral solution, other therapeutic agents should be selected. (See PRECAUTIONS and CLINICAL STUDIES sections.)

FDA Approves Fosfomycin Tromethamine (fosfomycin tromethamine) for Uncomplicated Urinary Tract Infections in WomenFDA approves new single-dose antibiotic for treating bladder infections in women

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FDA Approves Fosfomycin Tromethamine (fosfomycin tromethamine) for Uncomplicated Urinary Tract Infections in WomenFDA approves new single-dose antibiotic for treating bladder infections in women

Study Details

Intrawound tobramycin plus vancomycin did not reduce deep infection risk compared with vancomycin alone in high-risk tibial fractures

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Clinical research that matters. Delivered to your inbox.

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