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, though the infant should be monitored for bradycardia, hypoglycemia, and respiratory depression.
FDA Labeling and Excretion Profile
- The FDA label confirms that propranolol is excreted in human milk and recommends caution when administered to nursing women 1
- Neonates exposed to propranolol at parturition have exhibited bradycardia, hypoglycemia, and/or respiratory depression, indicating these are the key adverse effects to monitor 1
Quantitative Transfer Data
- Breast milk concentrations of propranolol peak 2-3 hours after maternal dosing and reach only 40-64% of peak maternal plasma concentrations 2
- The maximum cumulative propranolol dose a breastfed infant would receive is approximately 21 micrograms per 24 hours when the mother takes 40 mg four times daily (160 mg/day total), which is considerably less than therapeutic infant doses 2
- Another study found the infant would ingest only 0.1% of the maternal dose through breast milk, with an estimated daily intake of approximately 3-7 micrograms of propranolol per 100g of breast milk 3, 4
Clinical Recommendations
- There is no reason to advise women receiving propranolol to avoid breastfeeding, based on the minimal transfer and lack of reported adverse effects in multiple studies 3
- The infant should be monitored specifically for:
- Bradycardia (slow heart rate)
- Hypoglycemia (low blood sugar)
- Respiratory depression
- Signs of beta-blockade (decreased alertness, poor feeding) 1
Important Caveats
- While propranolol is generally compatible with breastfeeding, adequate monitoring facilities should be available given the potential for bradycardia and hypoglycemia in exposed infants 1
- The milk-to-plasma ratio is less than 1, meaning propranolol concentrates less in breast milk than in maternal blood 3
- Multiple prospective studies have shown no significant complications in breastfed infants, though one case of symptomatic hypoglycemia was reported in an infant whose mother received propranolol during pregnancy (not specifically attributed to breastfeeding exposure) 4