Propranolol Safety During Breastfeeding
Propranolol is safe to use during breastfeeding, as it transfers into breast milk in minimal amounts that are far below therapeutic infant doses, and breastfeeding can continue without interruption while taking this medication.
Evidence for Safety
The FDA label confirms that propranolol is excreted in human milk but recommends caution should be exercised when administered to nursing women 1. However, the pharmacokinetic data strongly support its safety profile during lactation.
Milk Transfer and Infant Exposure
- Propranolol concentrations in breast milk peak 2-3 hours after maternal dosing but remain only 40-64% of peak maternal plasma concentrations 2
- The estimated maximum daily infant exposure through breast milk is approximately 21 micrograms per day when the mother takes 40 mg four times daily (160 mg/day total), which is considerably less than therapeutic infant doses 2
- Actual measured infant intake from breast milk was approximately 3 micrograms daily in one study, with milk-to-plasma ratios less than 1 3
Clinical Recommendations
- Women already taking propranolol should continue the medication and breastfeed without interruption 2, 3
- No waiting period or "pump and dump" strategy is necessary after taking propranolol 3
- The umbilical cord plasma concentration at delivery is similar to maternal venous plasma, but this does not contraindicate breastfeeding 3
Important Monitoring Considerations
While propranolol is safe, the FDA label notes that neonates whose mothers receive propranolol at parturition may exhibit bradycardia, hypoglycemia, and/or respiratory depression 1. Therefore:
- Monitor infants for bradycardia (slow heart rate), hypoglycemia (low blood sugar), and respiratory depression, particularly in the immediate postpartum period 1
- These concerns are primarily relevant at delivery rather than during ongoing breastfeeding 1
- Adequate facilities for monitoring infants at birth should be available if the mother is taking propranolol 1
Practical Considerations
- Most medications are compatible with breastfeeding at recommended doses, and propranolol falls into this category 4
- Current evidence-based resources like LactMed provide authoritative safety information for medications during lactation 5
- The minimal transfer into breast milk makes propranolol substantially safer than many alternative medications that might be considered 2, 3