The idea in treating hyperthyroidism is to reduce the amount of thyroid hormone in the blood to normal. There are three main ways of doing this:
- Antithyroid drugs include tapazole and propylthiouricil. These block the production of thyroid hormone and reduce the autoimmune reaction that is taking place. You usually have to stay on the drug for at least a year. They can cause a reduction in white blood cells, making you more prone to infections.
- Radioactive iodine (RAI) will concentrate in the thyroid gland and gradually destroy thyroid cells. Unfortunately it is not possible to know exactly how much RAI to give to just destroy enough cells to reduce thyroid hormone production to normal so most people end up with low thyroid function and have to take a pill for the rest of their lives.
- Thyroid surgery is used to remove a part of the thyroid and leave just enough to provide normal thyroid hormone production. This too is hard to do and usually ends with the patient becoming hypothyroid, needing to take a pill lifelong.
Of these treatments, I prefer antithyroid drugs since only they have a chance of making the patient normal. By reducing the autoimmune reaction, they may reduce the possibility of eye disease and skin disease that sometimes accompanies hyperthyroidism. There is no rule that says you can’t take them more than a year. I have a few patients using them for two years and more. And I have many patients who have remained normal for years after stopping antithyroid drugs.