Can you take methenamine hippurate while breastfeeding?
What LactMed says
The National Library of Medicine’s own summary, quoted in full. We do not write a verdict of our own on this question, and we do not compress theirs into a label.
Methenamine passes into milk in small quantities and appears safe to use, even while nursing a newborn.
Quoted from Methenamine Hippurate — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised January 18, 2021.
What LactMed would consider instead
LactMed ends this record by naming the drugs it would consider in place of methenamine hippurate. Whether any of them fits depends on what you are treating — this is the database’s list, not a recommendation from us.
- Methenamine Mandelate
How much methenamine hippurate gets into breastmilk
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.
Infant Levels. Relevant published information was not found as of the revision date.
What has been seen in breastfed infants
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.
Effects on milk supply
Relevant published information was not found as of the revision date.
Frequently asked questions
Can you take methenamine hippurate while breastfeeding?
Methenamine passes into milk in small quantities and appears safe to use, even while nursing a newborn. The full record is quoted on this page, and the decision is one to make with the person who prescribed it — LactMed itself states it is not a substitute for professional judgement.
What can I take instead of methenamine hippurate while breastfeeding?
LactMed lists Methenamine Mandelate as alternate drugs to consider. That is the database's own list for this drug — whether any of them suits you depends on what you are treating.
Does methenamine hippurate pass into breastmilk?
LactMed's measured drug levels for methenamine hippurate are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking methenamine hippurate?
LactMed does not frame its records that way — it reports measured drug levels in milk and what has been observed in breastfed infants, which is what this page quotes. "Pump and dump" advice for a specific drug and dose should come from your clinician or a pharmacist, not from a general rule.
More on methenamine hippurate
LactMed states that the information it presents is not a substitute for professional judgement, and that you should consult your healthcare provider for breastfeeding advice related to your particular situation. Nothing on this page is medical advice.