Is Lasix (furosemide) safe to use during breastfeeding?

From the Guidelines

Furosemide (Lasix) is generally considered compatible with breastfeeding, though caution is advised, as it may decrease milk production in some women due to its fluid-reducing effects, and its use should be carefully considered in the context of the mother's and infant's health, as indicated by the most recent evidence from 2025 1.

Key Considerations

• The medication passes into breast milk, but levels are typically too low to affect the nursing infant.
• Monitoring of milk supply and infant weight gain is recommended.
• Staying well-hydrated can help maintain milk production.
• For nursing mothers with heart failure, hypertension, or edema requiring diuretic therapy, furosemide can be used when clinically necessary, but the lowest effective dose should be prescribed, as suggested by guidelines from 2022 1.

Safety and Efficacy

• The relative infant dose (RID) of furosemide is considered safe, with an RID of <10% 1.
• However, diuretics like furosemide may reduce milk production, and their use should be carefully considered, as noted in a study from 2020 1.

Clinical Recommendations

• If concerns arise about milk supply or infant effects, consultation with a healthcare provider is recommended to discuss timing doses to minimize infant exposure or alternative medications with better-established safety profiles during lactation.
• The decision to use furosemide during breastfeeding should be made on a case-by-case basis, taking into account the mother's and infant's individual needs and health status, as emphasized in the most recent guidelines from 2025 1.

From the FDA Drug Label

Because it appears in breast milk, caution should be exercised when Furosemide is administered to a nursing mother. Furosemide may inhibit lactation.

Lasix (furosemide) use during breastfeeding is not recommended without caution. The drug appears in breast milk and may inhibit lactation. Therefore, caution should be exercised when administering Furosemide to a nursing mother 2.

From the Research

Lasix and Breastfeeding

• There is limited information available on the use of Lasix (furosemide) during breastfeeding 3, 4.
• Most medicines can be used safely during breastfeeding at the recommended dose, however there are exceptions that necessitate caution 3.
• The use of medication by the nursing mother and the physician's advice to stop nursing are the most common reasons for the cessation of breastfeeding 4.
• Few drugs have been demonstrated to be absolutely contraindicated during breastfeeding, and clear, safe and reliable information is still lacking for most drugs 4.

Safety of Lasix During Breastfeeding

• There are no specific studies available on the use of Lasix during breastfeeding in the provided evidence.
• However, it is known that diuretics like furosemide can affect milk production and may pass into breast milk 5.
• The safety of Lasix during breastfeeding is not well established, and its use should be carefully evaluated on a case-by-case basis 6.

General Guidance on Medication Use During Breastfeeding

• Decisions regarding maternal medication use during breast feeding should be based on accurate and up-to-date information 7.
• Excellent sources of reliable information are reference books and online medical literature 4.
• If other medicines are required, information on their safety during breastfeeding can be accessed from pharmacy departments at maternity hospitals or from online resources 3.