Propranolol

Because of the low levels of propranolol in breastmilk, amounts ingested by the infant are small and would not be expected to cause any adverse effects in breastfed infants. Studies during breastfeeding have found no adverse reactions in breastfed infants clearly attributable to propranolol. No special precautions are required. Propranolol has been used successfully in cases of persistent pain of the breast during breastfeeding.[1]