Are Angiotensin Receptor Blockers (ARBs) safe to use during lactation?

From the Guidelines

Angiotensin Receptor Blockers (ARBs) are generally not recommended during lactation due to limited safety data and potential effects on the developing renal system of the infant. Most experts advise avoiding ARBs while breastfeeding and using alternative antihypertensive medications with better established safety profiles, such as labetalol, nifedipine, and methyldopa, which have minimal transfer into breast milk and established safety records 1. The concern with ARBs stems from their potential effects on the developing renal system of the infant, as these medications block the renin-angiotensin-aldosterone system which is important for kidney development. Some studies suggest that while there are few documented adverse effects in breastfed infants whose mothers took ARBs, the theoretical risks and limited data warrant caution 1. Any breastfeeding mother who must take an ARB should have her infant monitored for hypotension, poor feeding, lethargy, and adequate weight gain. Key points to consider when managing hypertension in lactating women include:

• Using alternative antihypertensive medications with established safety profiles
• Monitoring the infant for potential adverse effects if an ARB is necessary
• Considering the potential long-term cardiovascular consequences of gestational hypertension and the importance of lifestyle modifications to reduce maternal cardiovascular risk 1. It is essential to weigh the benefits and risks of using ARBs during lactation and to consider the most recent and highest quality evidence when making treatment decisions, such as the study published in Circulation in 2025 1.

From the Research

ARB Use During Lactation

• There is limited research directly addressing the safety of Angiotensin Receptor Blockers (ARBs) during lactation.
• A study from 2 provides an update on Angiotensin-Converting Enzyme Inhibitors (ACEIs) and ARBs with regard to lactation, but it does not offer conclusive evidence on the safety of ARBs during breastfeeding.

Potential Risks and Considerations

• Research on the use of ARBs during pregnancy suggests potential fetal toxicity, as seen in a case report 3, which may imply caution is needed when considering their use during lactation.
• Studies focusing on the use of ACEIs and ARBs during pregnancy, such as 4 and 5, highlight the importance of weighing the risks and benefits, especially considering the potential for congenital anomalies.
• The primary concern with ARBs and ACEIs is their impact on the renin-angiotensin system, which could potentially affect fetal development during pregnancy and, by extension, might raise concerns about their safety during lactation.

Lack of Direct Evidence

• There are no direct studies provided that specifically investigate the safety of ARBs during lactation, making it challenging to provide a definitive answer.
• The available evidence primarily discusses the use of ARBs during pregnancy and their effects on fetal development and maternal health, as seen in 3, 4, and 5.
• A study like 6 discusses the benefits of ARBs in patients with hypertension and chronic kidney disease but does not address lactation directly.

Considerations for Healthcare Providers

• Given the lack of direct evidence on the safety of ARBs during lactation, healthcare providers should exercise caution and consider alternative treatments when possible.
• If ARBs are deemed necessary for a lactating patient, close monitoring of both the mother and the infant for any potential adverse effects is recommended, based on the principles of pharmacovigilance and the precautionary principle, as might be inferred from studies like 3 and 2.