What are the treatment options for an overactive thyroid?

If the thyroid gland is producing too many hormones, the first step of treatment is usually to slow down the production of hormones using medication to reach a normal level. That needs to happen before other treatments can be started. The further treatment will depend on the cause:

• If the overactive thyroid is being caused by "autonomous" thyroid cells, the next step of treatment is often radioiodine therapy.
• If the thyroid gland has become very large, surgery to remove it is usually recommended.
• In Graves' disease, taking medication for about a year is often enough. But surgery or radioiodine therapy are often needed to make the thyroid function return to normal over the long term.

The choice of treatment doesn't only depend on what is causing the overactive thyroid. For instance, the medication isn't always well tolerated, and some people would rather not have surgery. It is then a good idea to discuss the available treatment options with the doctor.

The main medications used for the treatment of an overactive thyroid are known as anti-thyroid drugs. These reduce the production of thyroid hormones. Thiamazole (also called methimazole) and carbimazole are the most commonly used anti-thyroid drugs. If these drugs aren't tolerated, propylthiouracil is sometimes used. It is a good idea to discuss the pros and cons of these drugs with your doctor. The most common side effects of anti-thyroids include skin rashes, fever and joint problems. If a fever arises, it's important to see a doctor immediately because the fever could be a sign of a blood disorder – although this is rare.

Sometimes a medication called perchlorate is used instead. Perchlorate prevents iodine from being absorbed by the thyroid gland. Iodine is a trace element that the thyroid gland needs in order to produce hormones. An overactive thyroid that has access to a lot of iodine can also produce more hormones. Perchlorate is used in, for example, people who have an overactive thyroid and need to have an x-ray examination using an iodine-containing contrast medium (a dye-like substance) due to a different medical problem.

If the overactive thyroid causes a rapid or irregular heartbeat, a beta blocker (usually propranolol) can be taken too. People who have Graves' disease are sometimes given steroids.

If one single “autonomous” nodule is responsible for the thyroid being overactive, removing the nodule or the affected half of the gland is enough. If the whole gland is enlarged, and autonomous thyroid tissue or nodules are spread throughout it, usually the entire gland is removed either completely or with only a small part remaining. If the surgery is for Graves' disease the whole gland is typically removed.

As well as the general risks associated with surgery – such as bleeding, wound infections or wound healing problems – there's a risk that a certain nerve (called the recurrent laryngeal nerve) may become damaged during surgery. This can cause hoarseness and, in very rare cases, breathing problems.

Surgery may also cause damage to glands that regulate the calcium balance in the body, known as parathyroid glands. These approximately lentil-sized glands are located behind the thyroid gland. If thyroid surgery causes problems affecting the function of the parathyroid glands, they are usually only temporary. If they don't go away, calcium and vitamin D need to be taken regularly.

When the thyroid gland produces thyroid hormones, it absorbs iodine from the blood. Radioiodine therapy makes use of this: Radioactive iodine (radioiodine) is swallowed in the form of a capsule or dissolved in water. It is then absorbed by the thyroid gland, where it destroys overactive cells. This reduces the production of thyroid hormones. The amount of radiation is very low, and most of it leaves the body on its own within a few days. To avoid exposing other people and the environment to radiation, people who have radioiodine therapy in Germany stay in hospital for a few days. During this time, they stay in a special isolation room and generally aren't allowed to have visitors. The effects of radioiodine therapy only become noticeable after eight to twelve weeks.

Radioiodine therapy is not suitable for pregnant women and breastfeeding mothers. In people who have Graves' disease, radioiodine therapy might increase the risk of eye problems.

Although severe complications such as heart problems can occur in people who have radioiodine therapy, they are very rare. This can happen if the destroyed cells release stored thyroid hormones, temporarily increasing the level of these hormones in the blood. Because of this, people who are at higher risk of heart problems are advised to take anti-thyroid medication too if they have radioiodine therapy. Radioiodine therapy is currently not believed to increase the risk of cancer. But research in this area hasn't reached any clear conclusions.

People who have thyroid surgery or radioiodine therapy often have an underactive thyroid gland (hypothyroidism) afterwards. This is particularly likely if a lot of the thyroid gland was removed or many gland cells were destroyed. In people who have Graves' disease, the aim of surgery or radioiodine therapy is actually to completely remove or destroy all of the thyroid gland tissue.

The thyroid gland is then no longer able to produce thyroid hormones, so you usually have to take thyroid hormone tablets for the rest of your life. Taken at the right dose, the tablets are well tolerated. If the dose is too high, they may cause problems similar to the symptoms of an overactive thyroid, such as a rapid heartbeat.