Is Mavacamten 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 Mavacamten. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
No information is available on the use of mavacamten during breastfeeding. Because it is 97 to 98% plasma protein bound, the amount of mavacamten in milk is likely to be very low. If a mother requires mavacamten, it is not a reason to discontinue breastfeeding. Until more data become available, mavacamten should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.
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. Relevant published information was not found as of the revision date.
Infant Levels. Relevant published information was not found as of the revision date.
“No published information” means the studies do not exist yet — not that Mavacamten 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 “Mavacamten” (mavacamten). 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.