Can you take hydralazine 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.
Limited milk level and infant serum level data and a long history of use in postpartum mothers indicate that hydralazine is an acceptable antihypertensive in nursing mothers, even those nursing newborns.
Quoted from Hydralazine — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised November 15, 2024.
What LactMed would consider instead
LactMed ends this record by naming the drugs it would consider in place of hydralazine. Whether any of them fits depends on what you are treating — this is the database’s list, not a recommendation from us.
How much hydralazine gets into breastmilk
Maternal Levels. In one case report, a mother taking oral hydralazine 50 mg 3 times daily for at least 8 weeks postpartum had hydralazine milk levels of about 130 mcg/L at 0.5 and 2 hours after a dose. In addition, milk contained an amount of acid-labile hydrazones with undefined pharmacologic activity. The authors estimated that a breastfed infant would receive a maximum of 13 mcg per feeding at this maternal dosage.
Ten lactating women had blood and breastmilk samples analyzed within 24 hours after receiving a dose of hydralazine of between 10 and 40 mg in the first week postpartum. The analytic method measured hydralazine plus its pharmacologically active acid-labile metabolites. The average concentration of drugs in breastmilk was 240 nmol/L, which was about half of the simultaneous concentration in maternal plasma. The authors estimated that the daily dose to a breastfed infant would likely not exceed 25 mcg.
Infant Levels. Two infants were breastfed after their mothers had received a dose of hydralazine between 10 and 40 mg during the first week postpartum., At 2 hours after feeding, infant serum drug concentrations were 557 and 293 nmol/L. The analytic method measured hydralazine plus its pharmacologically active acid-labile metabolites. These values were much lower than those found in a 2 kg infant who was receiving hydralazine 6 mg/kg daily directly for coarctation of the aorta. Serum levels in this infant were 6230 nmol/L before a 4 mg dose, and 8050 and 8310 nmol/L at 2 and 4 hours after the dose, respectively. Two other infants who received sterilized (100 degrees C for 10 minutes) breastmilk from their mothers who were taking hydralazine had no detectable hydralazine in their serum 2 hours after receiving the breastmilk feeding. The authors showed that expressed milk concentrations from 2 mothers were 140 nmol/L before heating and <20 nmol/L after heating.
What has been seen in breastfed infants
No adverse effects reported in one infant breastfed for 8 weeks.
Effects on milk supply
Relevant published information was not found as of the revision date.
Frequently asked questions
Can you take hydralazine while breastfeeding?
What the NIH's Drugs and Lactation Database says about Hydralazine while breastfeeding — quoted in full. 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 hydralazine while breastfeeding?
LactMed lists Candesartan, Benazepril, Captopril, Lisinopril, Quinapril, Hydrochlorothiazide, Methyldopa, Propranolol 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 hydralazine pass into breastmilk?
LactMed's measured drug levels for hydralazine are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking hydralazine?
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 hydralazine
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.