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Antimicrobials

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Fosfomycin (Oral)

Guidelines for use

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1. Spectrum of activity

Active against:

  • Enterococcus faecalis
  • E. coli, including extended-spectrum beta-lactamase (ESBL) producing types

Note: While fosfomycin is noted to have in vitro activity against a number of other organisms, there are no guidelines on how to define susceptibility in the lab. Therefore, fosfomycin cannot be recommended to treat organisms other than E.faecalis and E.coli.

2. Clinical use

Appropriate use

  • Uncomplicated cystitis in women, including pregnancy
  • Asymptomatic bacteriuria in pregnancy

*Contact the Infectious Diseases Consult Service or the Antimicrobial Stewardship Team for consideration for off-label use.

Inappropriate use

  • Pyelonephritis
  • Perinephric abscess
  • Infections not related to the urinary tract, including bacteremia

3. Adverse effects

  • Diarrhea, nausea, vaginitis

4. Dosage

  • Uncomplicated cystitis or asymptomatic bacteriuria in pregnancy: 3 g po x 1 dose
    • Mix the contents of the single dose sachet with about ½ cup cold water, stir to dissolve and immediately take orally
  • Renal impairment:
    • no dosage adjustment is required for single doses (however, efficacy has not been well studied in this population)
    • no information is available on the efficacy and safety of oral fosfomycin in patients undergoing hemodialysis.

5. References

  1. Monurol® Product Monograph. Paladin Labs Inc. Date of Preparation: August 10, 2017.
  2. Gupta K, Hooton TM, Naber KG, Björn Wullt, Richard Colgan, Loren G. Miller, Gregory J. Moran, Lindsay E. Nicolle, Raul Raz, Anthony J. Schaeffer, David E. Soper, International Clinical Practice Guidelines for the Treatment of Acute Uncomplicated Cystitis and Pyelonephritis in Women: A 2010 Update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases, Clinical Infectious Diseases, Volume 52, Issue 5, 1 March 2011, Pages e103–e120
  3. Chu C, Lowder JL. Diagnosis and treatment of urinary tract infections across age groups. Am J Obstet Gynecol 2018;219:40-51.
  4. Keating GM. Fosfomycin Trometamol: A review of its use as a single-dose oral treatment for patients with acute lower urinary tract infections and pregnant women with asymptomatic bacteriuria. Drugs 2013;73:1951-1966.

Last updated: May 25, 2021