Graves' Disease Support Group

Hi and welcome, don't really know but I would call and ask him. Maybe they changed things?

Interesting...my endo told me PTU was the only one I could take while nursing. (I'm nursing my five mos old, while on PTU). Let me know if you find anything else out....

Decided to look around a little:
"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.) "

"As far as safety, a number of studies have found no alteration in thyroid function, or effects on thyroid function and physical and intellectual development in infants who are breastfed by mothers treated with daily doses of PTU, ranging from 50 to 300 mg, methimazole at doses of 5 to 20 mg, and carbimazole at doses of 5 to 15 mg) for as long as eight months. Because methimazole (Tapazole) and carbimazole cross into milk more readily, and only trace amounts of PTU cross into breast milk, PTU is considered preferable and safer for use by a nursing mother with hyperthyroidism."

Yes, PTU is a better choice for nursing moms.