Carbimazole

In Aotearoa New Zealand, carbimazole is available as tablets (5 mg). 

• The dose of carbimazole will be different for different people. The dose will depend on the severity of your condition and could be adjusted during the course of treatment.
• Treatment with carbimazole in adults is usually started at high doses (15 to 40 mg per day) for a few weeks until your thyroid returns to normal activity. The dose is then slowly reduced (to 5 to 15 mg per day) so that your thyroid gland can maintain its normal activity.
• Each day's tablets may be divided evenly into 2 doses (morning and evening), or 3 doses (morning, noon and night).
• Your healthcare provider will advise you how long to take carbimazole for (usually for 12 to 18 months).
• Always take your carbimazole exactly as your healthcare provider has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.

• Timing: Take each day's tablets divided evenly into 2 doses (morning and evening), or 3 doses (morning, noon and night). Try to take your carbimazole tablets at the same times each day. 
• Food: You can take carbimazole with or without food. 
• Missed dose: If you forget to take your dose, take it as soon as you remember. But if it's nearly time for your next dose, just take the next dose at the right time. Don't take double the dose. 
• If you have trouble remembering when to take your medicines see tips to help you remember to take your medicines regularly. You might find a medication reminder app helpful. 

Here are some things to know when you're taking carbimazole. Other things may be important as well, so ask your healthcare provider what you should know about.

• Other medicines: Carbimazole interacts with some medicines, herbal supplements and rongoā Māori, so check with your doctor or pharmacist before starting carbimazole and before starting any new products.
• Keep taking carbimazole regularly: It may take 4 to 8 weeks before you notice an improvement.  
• Monitoring: You'll need regular blood tests while you're taking carbimazole to make sure you're on the right dose.
• Contraception: If you’re taking high doses of this medicine and you could become pregnant, it’s recommended you use effective contraception while you’re taking carbimazole.
• Pregnancy or breastfeeding: Talk to your healthcare provider if you become pregnant, are planning a pregnancy or want to breastfeed.

Like all medicines, carbimazole can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.  

Sore throat or flu symptoms

Carbimazole can cause a drop in your white blood cells, which fight infection – a condition called neutropenia. This can put you at increased risk of getting infections. It's a rare but very serious side effect.

At the first sign of infection (eg, sore throat, fever, mouth ulcers, poor appetite, bruising, cold or flu symptoms, muscle aches or headache) contact your doctor for an urgent blood test to check your white blood cells. Read more about neutropenia.

Other side effects

Read more about medicines and side effects and reporting a reaction you think might be a side effect.