From the Guidelines
Losartan is considered to have limited safety data during lactation, but it can be used if the benefits to the mother outweigh the potential risks to the infant. According to the study published in Circulation 1, Losartan, an angiotensin II receptor antagonist, has limited safety data available, which may raise concerns about its use during breastfeeding. However, the same study provides Relative Infant Dose (RID) calculations for various antihypertensive medications, suggesting that medications with RID levels <10% are considered safe. Although Losartan's RID is not explicitly stated as being below this threshold, its use may be necessary for maternal health reasons.
In such cases, breastfeeding can continue while monitoring the infant for potential side effects such as low blood pressure, poor feeding, or lethargy, as suggested by general principles of medication use during lactation 1. It's also important to consider alternative antihypertensive medications with more extensive safety data in lactation, such as nifedipine or labetalol, especially for premature infants or neonates with immature kidney function. The benefits of breastfeeding typically outweigh the theoretical risks of Losartan exposure, and using the lowest effective dose and timing administration right after nursing can further minimize infant exposure.
Key points to consider when using Losartan during lactation include:
- Monitoring the infant for signs of low blood pressure, poor feeding, or lethargy
- Using the lowest effective dose of Losartan
- Timing administration of Losartan right after nursing to minimize infant exposure
- Considering alternative antihypertensive medications with more extensive safety data in lactation, if possible.
From the FDA Drug Label
It is not known whether losartan is excreted in human milk, but significant levels of losartan and its active metabolite were shown to be present in rat milk. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Losartan safety during lactation is uncertain. The FDA drug label states that it is not known if losartan is excreted in human milk, but it is present in rat milk. Due to the potential for adverse effects on the nursing infant, a decision should be made to either discontinue nursing or discontinue the drug, considering the importance of the drug to the mother 2.
- Key points:
- Uncertain safety during lactation
- Potential for adverse effects on the nursing infant
- Decision should be made to discontinue nursing or the drug
- Clinical decision: Due to the uncertainty and potential risks, it is recommended to exercise caution and consider alternative options for the mother or the infant.
From the Research
Losartan Safety During Lactation
- The safety of losartan, an angiotensin II receptor antagonist, during lactation is a concern due to its potential effects on the renin-angiotensin system in infants 3.
- Studies have shown that losartan and its active metabolite, EXP3174, are present in maternal milk during lactation, with estimated concentrations of 1.61 and 1.67 micrograms/ml, respectively 3.
- The presence of losartan in breast milk may pose a risk to the nursing infant, particularly in terms of renal development and function 4, 3.
- A study in rats found that oral losartan during lactation can cause irreversible renal structural changes and chronic kidney disease in adult life 4.
- However, there is limited information available on the safety of losartan during lactation in humans, and more research is needed to fully understand its effects 5, 6, 7.
Key Findings
- Losartan is excreted in breast milk, with detectable levels of the drug and its active metabolite 3.
- The use of losartan during lactation may be associated with an increased risk of renal problems in the nursing infant 4, 3.
- More research is needed to fully understand the safety of losartan during lactation in humans 5, 6, 7.
Relevant Studies
- A study on the toxicokinetics of losartan during gestation and lactation in rats found that the drug is present in maternal milk and may pose a risk to the nursing infant 3.
- A study on the use of angiotensin II receptor blockers during pregnancy found that these drugs should be avoided in pregnant women due to their potential fetal toxicity, but did not provide information on lactation 6.
- A review of antibiotic and analgesic use during lactation found that most drugs are considered safe for use during breastfeeding, but did not specifically address losartan 7.