Can I breastfeed while taking antithyroid drugs like Methimazole, Tapazole, or PTU, as a treatment for hyperthyroidism / Graves Disease?
Methimazole (Tapazole) may cause thyroid suppression and goiter in nursing infants. Most doctors would advise that this drug not be used, or if it were required, careful monitoring of the breastfeeding infant’s thyroid function would be needed, at intervals of every three months, at minimum, while the mother is on antithyroid drugs. According to the RxList drug information database online, “postpartum patients receiving Tapazole should not nurse their babies.” (Reference.) Whether or not a nursing mother with Graves’ Disease or hyperthyroidism should take the antithyroid drug propylthiouracil (PTU) is controversial. Some doctors believe that PTU use by a nursing mother, with regular monitoring of the infant’s thyroid function, is safe. They recommend careful monitoring of the breastfeeding infant’s thyroid function every three months while the mother is on antithyroid drugs, but because low amounts of PTU cross into the milk, they feel that it is safe for the infant. Breastfeeding educ
