Hyperthyroidism (Overactive Thyroid)

What are the treatments for hyperthyroidism?

The main aim of treatment is to reduce your level of thyroxine to normal. Other problems, such as a large goitre (thyroid swelling) or associated eye problems, may also need treatment. Factors such as the underlying cause of the problem, your age and the size of any goitre are taken into account to decide on the best treatment plan. Treatment options include the following:

Medicines – usually carbimazole

Medicines can reduce the amount of thyroxine made by the overactive thyroid gland. The most common medicine used is carbimazole and Propylthiouracil (PTU). Carbimazole does not affect the thyroxine which is already made and stored, but reduces further production. Therefore, it may take 4 to 8 weeks of treatment for your thyroxine level to come down to normal. The dose of carbimazole needed to keep the thyroxine level normal varies from person to person. A high dose is usually given initially which is then reduced as your thyroxine levels come down. 

Carbimazole is usually taken for 6-12 months at first. After this, in about half of cases, the condition will have settled down and the carbimazole can be gradually tapered and stopped. If the condition flares up again some time in the future, a further course may be needed. However, in these cases an alternative treatment (for example, radioactive iodine) is often recommended. In about half of cases, carbimazole needs to be continued long-term to control symptoms. A different treatment may then be a better option if you do not want to take carbimazole long-term. Warning: carbimazole can, rarely, affect your white blood cells which fight infection. If you develop a fever, sore throat, mouth ulcers or other symptoms of infection whilst taking carbimazole, you should stop taking it and see a doctor urgently for a blood test. Propylthiouracil is usually given instead of carbimazole if you are pregnant or breast-feeding.


This involves taking a drink, or swallowing a capsule, which contains radioactive iodine. The main use of iodine in the body is to make thyroxine. Therefore, the radioactive iodine builds up in the thyroid gland. As the radioactivity is concentrated in the thyroid gland, it destroys some thyroid tissue which reduces the amount of thyroxine that you make. The dose of radioactivity to the rest of the body is very low and is not dangerous. However, it is not suitable if you are pregnant or breast-feeding. In addition, after treatment, women should not become pregnant for at least six months and men are advised not to father children for at least four months. Also, following radioiodine treatment, you should avoid prolonged contact with others for a specified time. This may be for 2-4 weeks; depending on the amount of radioiodine you receive. The aim is to limit the exposure of radioactivity to others. For the specified period you will be advised to take precautions such as:

  • Limit close contact with babies, children or pregnant women. Close contact means being within one meter, for example, don’t cuddle children or allow them to sit on your lap.
  • You may wish to apply similar precautions as above for contact with your pets.
  • If you have children, or have a job where you have contact with children, you should discuss this with the specialist before treatment.
  • Stay more than an arm’s length away from other people.
  • Sleep alone.
  • Avoid going to places like cinemas, theatres, pubs and restaurants where you may be in close contact with other people.
  • Take some time off work if your work involves close contact with other people.

Your specialist will give detailed advice regarding these precautions.

Thyroid replacement therapy

It can be difficult for a doctor to judge just the right dose of carbimazole, or just the right amount of radioiodine, to give in each case. Too much treatment may make your thyroxine level go too low. Not enough treatment means your level remains higher than normal. Regular blood tests are needed to check on the thyroxine level. One option is to take a high dose of carbimazole each day deliberately, or to receive a one-off high dose of radioiodine. This stops your thyroid gland making any thyroxine. You will then need to take a daily dose of thyroxine tablets to keep your blood level of thyroxine normal. This over-treatment and then taking replacement thyroxine is also called ‘block and replace’.


This involves removing part of your thyroid gland. It may be a good option if you have a large goitre (thyroid swelling), which is causing problems in your neck. If too much thyroid tissue is removed then you will be given thyroxine tablets to keep your thyroxine level normal. It is usually a safe operation. But, as with all operations, there is a small risk.

Treatment for eye problems

You may need to see an eye specialist if you develop the eye problems of Graves’ disease. Relatively minor symptoms affect the eyes in about half of people with Graves’ disease. Measures such as artificial tears, sunglasses and eye protectors whilst you sleep may be sufficient to help. However, about 1 in 20 people with Graves’ disease have severe eye changes. Treatment can then be more difficult and may include surgery, radiation treatment or steroid tablets. If you smoke then it is important that you try to stop. Smoking can actually make your eye problems worse.

Beta-blocker medicines

Some people are given a beta-blocker medicine (for example, propranolol, atenolol, etc) for a few weeks whilst the level of thyroxine is reduced gradually by one of the above treatments. Beta-blockers can help to reduce symptoms of tremor, palpitations, sweating, agitation and anxiety.


Regular checks are recommended, even after you finish a successful treatment. It is very important to have a regular blood test (at least every year) to check that you have the right level of thyroid hormone (thyroxine) in your blood. Your GP may do this test. This is because some people become hyperthyroid again sometime in the future. Others who have been treated successfully develop an underactive thyroid in the future. If this occurs it can usually be treated easily with thyroxine tablets.

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