My Dr. Prescribed Iodoral For My Hoshimoto's. That Dr. Is

My Dr. prescribed Iodoral for my Hoshimoto's. That Dr. is no longer in practice. Recent bloodwork showed my Iodine levels at 490. Obviously the 50 mg of Iodoral was too high. My new Dr. wants me to discontinue the Iodoral. What health implications are there for having had such a high level for the past year? What concerns should I have regarding cold turkey discontinuation? I also take Synthroid and T-4. Thanks!