Is Diltiazem 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 Diltiazem. The text below is quoted from that source — it is not our own verdict.

Summary of use during breastfeeding

Based on limited data, amounts of diltiazem ingested by the infant are small and would not be expected 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. In one patient who was 14 days postpartum, peak milk levels of 190 to 230 mcg/L occurred about 2 hours after the dose during an oral regimen of 60 mg four times daily. The levels and time course of the drug in milk closely paralleled serum levels.[1] Using the peak milk level data from this patient, an exclusively breastfed infant would receive an estimated maximum of 0.9% of the maternal weight-adjusted dosage.

Infant Levels. Relevant published information was not found as of the revision date.

Alternatives LactMed lists

Diltiazem in pregnancy

LactMed covers breastfeeding only. For what the NHS and the US prescribing label say about pregnancy, see:

“No published information” means the studies do not exist yet — not that Diltiazem 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 “Diltiazem” (LM94). 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.