Can I take losartan while pregnant or breastfeeding?

8.1 Pregnancy Risk Summary Losartan potassium can cause fetal harm when administered to a pregnant woman. Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensive use in the first trimester have not distinguished drugs affecting the renin-angiotensin system from other antihypertensive agents. When pregnancy is detected, discontinue losartan potassium as soon as possible (see Clinical Considerations). The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Prescribing label, section “8.1 Pregnancy” (opening excerpt): Losartan Potassium (oral), Redpharm Drug. Read the full section on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.

Because no information is available on the use of losartan during breastfeeding, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.

“Summary of Use during Lactation”, LactMed record “Losartan” (LM726), quoted verbatim. Everything LactMed reports about Losartan while breastfeeding.

8.2 Lactation Risk Summary 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.

Prescribing label, section “8.2 Lactation”: Losartan Potassium (oral), Redpharm Drug. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.