Is Methenamine Mandelate safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Methenamine Mandelate. This is a summary of that source — not our own verdict.
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 ] Six infants were allowed to nurse during maternal ingestion of the large daily dosage of 12 grams of mandelic acid. There was no clinical or laboratory evidence of harm to the infants.[ 2 ]
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 ] Six mothers were given mandelic acid 3 grams orally 4 times daily, a dose far in excess of that contained in a typical dose of methenamine mandelate. The authors estimated that their exclusively breastfed infants received an average 273 mg of mandelic acid daily in breastmilk. This amounted to an average daily dosage of 86 mg/kg in the 6 infants, which is about 48% of the adult dosage.[ 2 ] Infant Levels. Relevant published information was not found as of the revision date.
Alternatives LactMed lists
Source: NIH LactMed (National Library of Medicine).
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.