Fosfomycin

C. diff Risk

Low

Oral Bioavailability

Moderate

Approximate Cost

Spectrum Of Activity

Dosing

** Non-Formulary, obtain infectious disease and P&T approval**

Female, Uncomplicated UTI
3 g PO once

Complicated or male UTI
3 g PO every 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

  • Salvage therapy for UTI due to multi-drug resistant organisms (e.g. VRE, ESBL)

Unacceptable Uses

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

Common Usage

Urinary Tract Infection, especially involving ESBL producing organisms

Off label - Prostatitis

Not recommended in pyelonephritis

Adverse Effects

  •  GI upset, especially diarrhea

  •  Headache

  •  Eosinophilia, neutropenia

  •  Hypokalemia

Major Interactions

No significant interactions

Pharmacology

Antimicrobial class: Phosphonic acid derivative

Pregnancy category: B

Average serum half life: 6 hours

Urine penetration: Therapeutic