It is very common for me to see breastfeeding women in my lactation clinic who are taking medications for high blood pressure, so it is reasonable for all lactation providers to be aware of what high blood pressure medications might be unsafe. The easiest way to know is to look up the medication in the National Library of Medicine’s LactMed, and share this resource with the mother, so that she can show it to her physician or other health care provider. Diuretics in high doses can decrease the milk supply, and Dr. Anderson points out that historically it was used to suppress lactation postpartum. The relatively low doses that we use for high blood pressure or even postpartum cardiomyopathy appear to be safe. However, I suggest observing the milk supply carefully. Among the ACE inhibitors, lisinopril is the least studied medication and for now should be avoided. Labetolol is a beta blocker that is often continued from pregnancy to postpartum. Beta blockers can cause more infant side effects, particularly for premature infants, so it would be reasonable for OB providers to consider shifting the postpartum medication to nifedipine or benazepril rather than using labetolol.

It is reasonable to avoid guanfacine for hypertension during lactation because we have no evidence regarding its effect on infants, and it might have a negative effect on a mother’s prolactin level.