Carbimazole is a medicine used to treat an overactive thyroid (hyperthyroidism). This is when your thyroid gland makes too much thyroid hormones.
Your thyroid controls things like your heart rate and body temperature. When it makes too much hormones, you can have symptoms such as weight loss, mood swings and feeling irritable.
Carbimazole helps to ease these symptoms by reducing the amount of hormones your thyroid makes.
It usually comes as tablets and is only available on prescription. If you are unable to swallow tablets, your doctor may be able to prescribe carbimazole as a liquid.
Sometimes your doctor will prescribe carbimazole together with a beta blocker. This can help with your symptoms if you have a fast heartbeat, or feel irritable or anxious.
Key facts
- You'll have blood tests before and during treatment with carbimazole.
- You may start to feel better after 1 to 3 weeks of taking carbimazole but it can take 1 to 2 months before the medicine works fully.
- Side effects usually happen in the first 8 weeks and tend not to last long.
- One rare side effect can be a sudden drop in your white blood cell count. This makes it harder to fight infections.
- If you're pregnant, your dose of carbimazole needs to be monitored carefully.