Side Effects Of Carbimazole

Like all medicines, carbimazole can cause side effects, although not everyone gets them. If you do have side effects, these usually happen in the first 8 weeks of taking carbimazole.

Side effects of carbimazole

Side effects usually improve as your body gets used to carbimazole. There are things you can do to help cope with them:

Talk to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.

Serious side effects

Serious side effects are uncommon.

Stop taking carbimazole and call your doctor or 111 now if:

• you have a high temperature, sore throat, mouth ulcers, severe tiredness or flu-like symptoms - these can be signs of a low white blood cell count
• you feel generally unwell or think you may have an infection
• you notice you are bruising or bleeding more easily

Call your doctor or 111 straight away if:

• the whites of your eyes turn yellow, or your skin turns yellow (this may be less obvious on brown or black skin), or you have dark pee - this can be a sign of liver problems
• you have swollen glands
• you feel faint, and sweaty - these can be signs of low blood sugar
• you have muscle pain or weakness - these can be signs of muscle problems
• you have nerve pain - this could be burning, stabbing or shooting pain
• you have kidney problems, such as passing less pee (urine), water retention, or blood in your pee
• you have sudden severe stomach (abdominal) pain - this can be a sign of an inflamed pancreas (acute pancreatitis)

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to carbimazole.

Call 999 now if:

• your lips, mouth, throat or tongue suddenly become swollen
• you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
• your throat feels tight or you're struggling to swallow
• your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
• you suddenly become very confused, drowsy or dizzy
• someone faints and cannot be woken up
• a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)

You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.

These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

Other side effects

These are not all the side effects of carbimazole. For a full list see the leaflet inside your medicine packet.

Reporting side effects

You can report any suspected side effect using the Yellow Card safety scheme.

Visit the Yellow Card website for more information about reporting side effects.

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