context: There are several different ways to treat an overactive thyroid (hyperthyroidism). Before choosing the one that's best for you, your doctor will consider what's causing it, your age, your overall heath, and how severe your symptoms are. This is a medication you take by mouth to help shrink your thyroid. It generally takes 3 to 6 months to work. Because taking this medication makes your thyroid slow down, there's a risk that you can develop hypothyroidism. When that happens you have an underactive thyroid. If you develop hypothyroidism, you may need to take daily medication to help replace your thyroid hormones. Doctors have used radioactive iodine to treat hyperthyroidism for over 60 years. It's generally considered safe, and it is used to treat more than 70% of adults with hyperthyroidism. In some cases, an overactive thyroid is treated with medicines that block its ability to produce thyroid hormones. Methimazole and propylthiouracil help control the symptoms and can have long-term benefits. These medicines will typically relieve your symptoms within 3 months, although you will likely need to stay on them for up to 18 months to help lessen the chance of a relapse. Methimazole has less-severe side effects, so it's prescribed more often. Up to 3% of people who take antithyroid medications develop allergic reactions like rashes and hives. In rare cases, these medicines can cause a condition called agranulocytosis, which decreases the number of your white blood cells. When this happens, you're more likely to develop an infection. There's also the risk of liver damage. See your doctor right away if you develop symptoms like a fever or sore throat while taking these drugs. These medications don't change the amount of thyroid hormone in your body, but they can help you feel better by controlling your symptoms. Beta-blockers affect the way thyroid hormone acts on your body. They're most often used to treat high blood pressure. They can also help slow down your heart rate and keep it beating regularly. Side effects may include: Headache Dizziness Digestive problems Surgery isn't typically recommended for an overactive thyroid. But if you can't take antithyroid medicines or get radioactive iodine therapy, your doctor may recommend a surgery called thyroidectomy. It means your thyroid will be completely removed. This surgery comes with some risks. It can damage your vocal cords and your parathyroid glands, which are located at the back of your thyroid. These glands help control the amount of calcium in your blood. If you have the operation, you'll need to take medicine for the rest of your life to provide your body with the right amount of thyroid hormone. If your parathyroid glands are also removed, you may need a medication to keep the calcium levels in your blood where they should be. If your hyperthyroidism is caused by Graves' disease, you may have a condition that affects your eyes. This is called Graves' orbitopathy or ophthalmopathy. If your symptoms aren't severe, you can usually manage them by avoiding bright lights and wind, raising the head of your bed, and using eye drops. Your doctor may suggest a selenium supplement. In some cases, you might need to take steroids or other medications to help control the swelling behind your eyes. For some people with Graves' ophthalmopathy, surgery is the best option. There are two kinds that can help severe symptoms: Orbital decompression surgery involves removing the bone between your sinuses and eye socket. It can help by making extra room for your eyes so that they go back to their normal position. It can help improve your vision. There are risks to the surgery, including double vision. Eye muscle surgery is sometimes used to correct double vision. It works by cutting muscles in your eyeball that are covered in scar tissue. Graves' ophthalmopathy can cause this. The cut muscles are then reattached in a different position, which can put your eyes back in proper alignment. You may need this surgery more than once to get the right results.