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

Summary of use during breastfeeding

Limited information indicates that maternal doses of 4 mg daily produce low very levels in milk 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 in nursing mothers was not found as of the revision date. However, the pharmacologically similar drug prazosin does not affect serum prolactin concentration in patients with hypertension,[3,4] indicating that doxazosin may not affect prolactin levels. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Levels in milk

Maternal Levels. A woman who was nursing a 6-month-old infant received 2 doses of doxazosin 4 mg 24 hours apart. Four milk samples were obtained after the second dose. A peak milk level of 4.2 mcg/L occurred at 1 hour after the dose. The average concentration over the 18-hour study period was 2.9 mcg/L. The authors estimated that a fully breastfed infant would receive an average daily dosage of 440 ng/kg daily or about 0.6% of the maternal weight-adjusted dosage.[1]

A woman with pheochromocytoma during pregnancy was treated near term with doxazosin and metoprolol. She continued doxazosin for 3 days postpartum until adrenal surgery. Thirty hours after her last dose of 8 mg of doxazosin, the drug was undetectable (<25 mcg/L) in her breastmilk.[2]

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

Alternatives LactMed lists

Doxazosin in pregnancy

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

Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Doxazosin” (LM745). 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.