Is Lasix (furosemide) contraindicated in breastfeeding mothers?

Furosemide (Lasix) Use During Breastfeeding

Furosemide (Lasix) is not contraindicated during breastfeeding, but caution should be exercised as it appears in breast milk and may potentially inhibit lactation.

Evidence on Furosemide and Breastfeeding

The FDA drug label for furosemide specifically states: "Because it appears in breast milk, caution should be exercised when Furosemide is administered to a nursing mother. Furosemide may inhibit lactation" 1. This is the most direct and authoritative guidance on this medication during lactation.

While furosemide is not listed among medications absolutely contraindicated during breastfeeding, there are two primary concerns:

1. Presence in breast milk: The medication is transferred into breast milk
2. Potential effect on milk production: Furosemide may inhibit lactation

Risk Assessment Framework

When evaluating the use of furosemide in breastfeeding mothers, consider:

• Maternal need: Is the medication essential for the mother's health?
• Infant age and health: Younger infants (especially <6 weeks) require more caution 2
• Alternative medications: Are there diuretics with better safety profiles during lactation?
• Monitoring: Watch for signs of decreased milk production and infant dehydration

Clinical Recommendations

1. Discuss benefits vs. risks: The benefits of treating maternal conditions often outweigh minimal risks to the infant

2. Consider timing strategies:

   • Administer furosemide immediately after breastfeeding
   • Allow maximum time between medication administration and next feeding

3. Monitor the infant for:

   • Adequate hydration
   • Normal weight gain
   • Changes in feeding patterns

4. Monitor maternal milk supply: Watch for decreased production, as furosemide may inhibit lactation 1

Important Considerations

• Most medications appear in breast milk in only small amounts 3, but furosemide specifically notes potential for inhibiting lactation
• The American Academy of Pediatrics notes that only a small proportion of medications are contraindicated during breastfeeding 4
• When assessing medication safety during breastfeeding, consider both the pharmacokinetics and the potential impact on lactation 5

Practical Approach

For breastfeeding mothers requiring diuretic therapy:

1. Consider if the diuretic is absolutely necessary
2. Use the lowest effective dose
3. Monitor milk supply closely
4. Ensure infant hydration and weight gain remain adequate
5. Consider alternative diuretics if milk supply appears affected

Conclusion

While furosemide is not absolutely contraindicated during breastfeeding, its potential to inhibit lactation warrants caution. The decision to use furosemide should balance the mother's medical needs against potential impacts on breastfeeding, with close monitoring of both maternal milk production and infant well-being.