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Fosfomycin Pregnancy and Breastfeeding Warnings

Fosfomycin is also known as: Monurol

Medically reviewed on June 26, 2018

Fosfomycin Pregnancy Warnings

Fosfomycin sodium (IV): This drug should not be used during pregnancy unless the benefit outweighs the risk.
Fosfomycin tromethamine/trometamol (oral): This drug should be used during pregnancy only if clearly needed.

US FDA pregnancy category: B (fosfomycin tromethamine)

Animal studies have revealed evidence of fetotoxicity, but only at doses which also resulted in maternal toxicity. When administered as the sodium salt (IM injection), fosfomycin crosses the placental barrier in humans. There are no controlled data in human pregnancy.

A single 3 g oral dose of fosfomycin tromethamine was given (in water) to 153 pregnant women with bacteriuria. Infecting organisms were eradicated in 96% of patients, with recurrence rate of 3% after 25 to 30 days. Minimal maternal side effects occurred and no serious adverse fetal effects were documented. The trimester in which the drug was administered was not reported.

US FDA pregnancy category B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

See references

Fosfomycin Breastfeeding Warnings

LactMed: This drug is not expected to cause harmful effects in the nursing infant, especially if older than 2 months.
-Fosfomycin sodium (IV): Use is not recommended unless the benefit outweighs the risk.
-Fosfomycin tromethamine/trometamol (oral): A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Yes (low levels)

Low levels were found in human milk (about 8% of serum levels).

After 1 to 2 g via injection, colostrum levels in 2 women were 4.8 mg/L and milk levels were 3.6 mg/L.

See references

References for pregnancy information

  1. "Product Information. Monurol (fosfomycin)." Forest Pharmaceuticals, St. Louis, MO.
  2. Zinner S "Fosfomycin trometamol versus pipemidic acid in the treatment of bacteriuria in pregnancy." Chemotherapy 36(suppl 1 (1990): 50-2
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  4. Reeves DS "Treatment of bacteriuria in pregnancy with single dose fosfomycin trometamol: a review." Infection 20(suppl 4 (1992): s313-6

References for breastfeeding information

  1. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL:" ([cited 2013 -]):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. "Product Information. Monurol (fosfomycin)." Forest Pharmaceuticals, St. Louis, MO.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.