Is Methenamine Hippurate 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 Methenamine Hippurate. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Methenamine passes into milk in small quantities and appears safe to use, even while nursing a newborn.
Effects on the breastfed infant
Four newborn infants were allowed to breastfeed in one study after a maternal dose of 1 gram of methenamine hippurate. No adverse effects were reported.[1]
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Maternal Levels. Six mothers nursing newborn infants were given methenamine hippurate 1 gram orally. Five hours after the dose, a mean methenamine concentration of 7 mg/L was found in milk. In two other women, milk concentrations averaged 9.1 mg/L at 2 to 3 hours after a 1 gram dose of methenamine hippurate orally and 4.3 mg/L at 6 to 7 hours after the dose. Based on the amount of milk ingested, the authors calculated the dose the infants received to be 0.05 to 0.1 mg/kg, which is about 1% of the adult dose.[1]
Infant Levels. Relevant published information was not found as of the revision date.
Alternatives LactMed lists
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Methenamine Hippurate” (LM829). 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.