Propranolol in human plasma and breast milk

Area of Science:

• Pharmacology
• Neonatal Medicine
• Maternal Health

Background:

• Propranolol is frequently prescribed for various maternal conditions.
• Concerns exist regarding propranolol transfer into breast milk and infant safety.
• Limited data is available on propranolol pharmacokinetics in lactating women.

Purpose of the Study:

• To quantify propranolol concentrations in maternal plasma and breast milk.
• To assess the infant's cumulative propranolol exposure during breastfeeding.
• To evaluate the safety of continuing propranolol therapy for breastfeeding mothers.

Main Methods:

• Simultaneous measurement of propranolol in maternal plasma and breast milk.
• Administration of single (40 mg) and continuous (40 mg 4x daily) propranolol doses.
• Calculation of infant's potential daily propranolol intake via breast milk.

Main Results:

• Propranolol levels in breast milk were significantly lower than in maternal plasma.
• Peak breast milk concentrations were 40% (single dose) and 64% (continuous dose) of peak plasma levels.
• Estimated infant daily dose was substantially below therapeutic levels for infants.

Conclusions:

• Continuing propranolol therapy during breastfeeding results in minimal infant exposure.
• The estimated infant dose is considerably lower than the usual therapeutic dose for infants.
• Propranolol therapy can likely be safely continued in breastfeeding mothers.