C. diff Risk


Oral Bioavailability


Approximate Cost




Female, Uncomplicated UTI
3g PO once

Complicated or male UTI
3g PO q 2-3 days x 3 doses

General Information

Acceptable Uses

  • Management of uncomplicated UTI in patients with multiple antibiotic allergies and when oral therapy is indicated.

  • Uncomplicated UTI due to VRE in patients with documented penicillin allergy.

  • Salvage therapy for UTI due to multidrug-resistant organisms (e.g. ESBL, VRE, ┬▒Pseudomonas) on a case by case basis.

Unacceptable Uses

  • Never use fosfomycin for management of infections outside the urinary tract because the oral formulation does not achieve adequate concentrations at other sites.

Common Usage

Urinary Tract Infection, especially involving ESBL producing organisms

Off label - prostatitis; extended course. Caution advised due to lack of data in long-term use and in prostatitis.

Not recommended in pyelonephritis

Adverse Effects

  • GI upset, esp. diarrhea

  • Headache

  • Eosinophilia, neutropenia

  • Hypokalemia

Additional Information

  • Nonformulary

  • IV formulation not available


Antimicrobial class: Phosphonic acid derivative

Pregnancy category: B

Average serum half life: 6 hours

Urine penetration: Therapeutic