Is Fosfomycin safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Fosfomycin. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Limited information indicates that fosfomycin produces low levels in milk and is unlikely to be absorbed well by the infant because of the binding to calcium in the milk.[1] It is unlikely to cause any adverse effects in breastfed infants.
Effects on the breastfed infant
Relevant published information was not found as of the revision date.
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Maternal Levels. After 1 to 2 grams of fosfomycin given by injection, colostrum levels in 2 women were 4.8 mg/L and milk levels were 3.6 mg/L.[2,3] Further details of the studies were not given.
Infant Levels. Relevant published information was not found as of the revision date.
Alternatives LactMed lists
“No published information” means the studies do not exist yet — not that Fosfomycin is known to be harmful, and not that it is known to be safe. Your prescriber or pharmacist can weigh your baby's age and whether a better-studied alternative would do the same job. Worth asking before stopping a medicine you need.
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Fosfomycin” (LM478). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.