Excretion of antihypertensive medication into human breast milk: a systematic review

To establish which antihypertensive medications are safe for use while breastfeeding, by reviewing the available evidence.

Reports of studies examining the transfer of antihypertensive medications to breastmilk were identified from multiple MEDLINE and EMBASE searches, manual review of bibliographies of articles and textbooks on drug use during lactation. The reports were reviewed and the results were compiled.

Prospective cohort studies and case reports constituted the only available evidence. Compilation of these results found that the milk to plasma (M/P) ratios varied widely across the beta-blocker family, the beta-blockers with low protein binding having the highest M/P ratios. The angiotensin-converting enzyme (ACE) inhibitors, methyldopa, and some calcium channel blockers had low M/P ratios.

The available data to date indicate that ACE inhibitors, methyldopa, beta-blockers with high protein binding, and some calcium channel blockers all appear to be safe treatments of hypertension in a nursing mother. The data suggest that drugs to be avoided are beta-blockers with low protein binding. However, the available evidence is limited and further studies are needed to confirm these findings.