Is Methyldopa 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 Methyldopa. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Because of the low levels of methyldopa in breastmilk, amounts ingested by the infant are small and would not be expected to cause any adverse effects in breastfed infants. No special precautions are required.
Effects on the breastfed infant
No acute or long-term adverse effects were reported in any 15 infants ranging in age from less than 1 week to 8 weeks of age whose mothers were taking oral methyldopa 0.25 to 1.5 grams daily.[1-4]
Effects on milk supply
Methyldopa can increase serum prolactin and has caused galactorrhea.[5-8] The maternal prolactin level in a mother with established lactation may not affect her ability to breastfeed.
Levels in milk
Maternal Levels. Three women who were 2 to 15 days postpartum were taking 250 mg of methyldopa orally 3 or 4 times daily. Randomly drawn milk samples had levels of drug and conjugate that ranged from < 0.1 to 0.5 mg/L at a dose of 750 mg daily and were 0.8 mg/L at a dose of 1 gram daily.[1]
In 3 women who were 1 to 8 weeks postpartum, peak levels of drug and conjugate occurred between 3 and 6 hours after the dose. Peak levels of drug and conjugate after a dose of 500 mg were 0.2, 0.66 and 1.14 mg/L in 3 mothers' milk. The authors estimated an infant dosage of less than 0.2% of the mother's total dosage.[2]
Infant Levels. No methyldopa was detectable (<200 mcg/L) in the serum of an infant whose mother was taking methyldopa 250 mg twice daily. The infant's urine contained a methyldopa concentration of 3.8 mg/L.[3]
In an 8-week-old infant whose mother was receiving 1 gram daily of methyldopa, a serum level of 90 mcg/L was found 10 hours after a 500 mg maternal dose. Another 1-week-old infant whose mother was receiving 500 mg daily had no detectable drug in the serum (<50 mcg/L).[2]
Alternatives LactMed lists
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Methyldopa” (LM179). 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.