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Alternatives to carbimazole for overactive thyroid

I was diagnosed with overactive thyroid and prescribed carbimazole. I went to see an endocrinologist and they suggested two different treatments, radioactive iodine or an operation to remove the thyroid. I would like to ask for a 2nd opinion – whether there is/are any other better treatments available? Thanks

1 March 2021

Overactive thyroid (or hyperthyroidism) is when the thyroid gland produces excessive amounts of thyroid hormones, which can significantly speed up the body’s metabolism, resulting in symptoms including sudden weight loss, rapid or irregular heartbeat, sweating, tiredness and irritability. Click on the link below for more information on the signs and symptoms of overactive thyroid, and when to see your GP: 

Symptoms of overactive thyroid (hyperthyroidism) – NHS Factsheet

Treating overactive thyroid with medication

Carbimazole is a medicine used in the treatment of overactive thyroid. Another is propylthiouracil. Both work by reducing the amount of natural thyroxine hormone produced in the body.

Treatment usually starts with a high dose of the drug, but the actual dose will depend on the individual. This will take several weeks to come into effect because the body needs to use up the excess of thyroid hormones already in your body, before levels start to decrease.

Typically, you’ll be reviewed by your doctor and have a blood test 4-6 weeks after you start taking carbimazole for the first time. The blood test is to check your thyroid levels. Depending on the results the dose may need to be adjusted.

Your doctor will continue to monitor your progress in this way with blood tests every 3-6 months until your thyroid levels return to within the normal range.

Side effects of carbimazole

Reported side effects of carbimazole that some people experience include:

  • Upset stomach/feeling sick 
  • Headaches
  • Aching joints
  • Itchy rash.

These usually stop after the first couple of months, as your body adjusts to the medication.

Rarely, carbimazole can cause a decrease in white blood cell levels, which can make you vulnerable to infection. Signs of a problem include:

  • Sore throat
  • Mouth ulcers
  • Fever
  • Unexplained bruising or bleeding.

If you experience any of these you should contact your doctor straight away for a blood test.

In some people this medicine may be enough to treat the overactive thyroid and return thyroid function to normal.

Alternatives to carbimazole in the treatment of hyperthyroidism

If your overactive thyroid isn’t responding to medication effectively, this is when your endocrinologist would consider the alternative treatment options: radioiodine or thyroid surgery.

Radioiodine therapy

Radioiodine therapy is where radiation is used to damage or destroy some of the thyroid tissue, thereby reducing the amount of hormone you produce. Administered orally as a capsule or drink, it’s a highly effective treatment that can cure an overactive thyroid, usually in a single treatment. This option is not suitable if you’re pregnant, breast feeding, are experiencing vomiting or incontinence, or have severe eye problems as a result of your condition. You can find out more about radioiodine therapy by clicking on the following link:

Thyroid surgery

Thyroid surgery involves removing part or all of the thyroid gland. This is usually considered the best option if your thyroid gland is severely swollen (a condition known as goitre), if you have severe eye problems resulting from your overactive thyroid, or if other treatments have failed, or your symptoms have returned following the above treatments. If all of the thyroid is removed you’ll need to take medication (levothyroxine) for the rest of your life to replace the missing thyroxine hormone.

If you’d like to see another endocrinologist for a second opinion please contact your GP. Or, if you’re an AXA Health member you may be eligible for our Second Opinion service, that’s there to provide added peace of mind for when you’re not satisfied with your initial consultation. Please contact your claims team to discuss this option and arrange an appointment if appropriate.

Answered by the Health at Hand team.

Useful resources

Overactive thyroid (hyperthyroidism) - NHS factsheet

The British Thyroid Association

Thyroid UK

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