NZ Formulary



What does it do?

Carbimazole reduces the amount of thyroid hormone made by your thyroid gland.

Before you start

  • Tell your doctor if you have liver problems.
  • Tell your doctor if you are pregnant or breastfeeding. If you are planning to get pregnant or find that you are, discuss this with your doctor. Use reliable contraception while taking carbimazole.
  • You will need a blood test to check your liver and your blood cells.

How should you take it?

Take carbimazole regularly as directed with a glass of water. You can take it with or without food.

What if you forget a dose?

Take the missed dose as soon as possible and continue as directed.

Can you take other medicines?

Some medicines available without a prescription may react with carbimazole including:

  • iodine supplements

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products (e.g. kelp) or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Reduced number of blood cells that fight infections or help your blood to clot - symptoms include: fever, chills, sore throat or generally feeling unwell, or easy or unusual bruising or bleeding

Symptoms of liver problems including: yellow skin or eyes, itching, dark urine, pale bowel motions, abdominal pain

Severe stomach pain, nausea

Tell your doctor immediately

Skin rash

Tell your doctor

Joint, muscle or bone aches and pains

Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Important information continues on next page.

Other information:

  • You will need regular blood tests while you are taking carbimazole to make sure you are on the right dose.