Antithyroid drugs such as propylthiouracil and methimazole (Tapazole), which interfere with thyroid hormone production, can be used to treat Graves' disease. After you begin treatment, it may take several months for hyperthyroid symptoms to subside. This is because the thyroid has already generated and stored enough hormone to keep it circulating at elevated levels. Once the stores are drained, hormone production should drop to its normal level. Although your disease may seem to go away entirely, you might still need drug therapy to keep your thyroid operating properly. Even if your Graves' disease does go into remission and your doctor says it's safe to stop taking medication, you'll need to be evaluated every year or so to make sure hyperthyroidism has not returned since relapse is common.