My doctor took me off Tapazole a couple of times. The first time (after 9 months of Tapazole-induced hypothyroidistic misery) I was hyperthyroid again in a month. I went back on for another year, supplementing with Synthroid to keep from being hypothyroid. I went off Tapazole again in September 1999, although I continued on a low dose of Synthroid. As of my last test in Feb 2000, I am euthyroid. I go back to the doctor on 6/1.