About the posting on the mom with hyperthyroidism being told she has a need for weaning (partial) if given meds...this is not my experience. The reference Clinical Drug Data does a nice comparison of PTU and Tapazole. Tapazole has much less secretion into breastmilk than PTU; I did review the study cited on Tapazole (generic = methimazole) and was impressed that the drug really seems ok. I still would watch the baby closely and periodically check thyroid levels, but it would be fine to nurse freely while on the drug.-Anne Eglash MD