Patient Leaflet Updated 21-May-2026 | Aurobindo Pharma - Milpharm Ltd.
Carbimazole 5 mg and 20mgTablets
Carbimazole 5 mg tablets
Carbimazole 20 mg tablets
1. What Carbimazole is and what it is used for
2. What you need to know before you take Carbimazole
3. How to take Carbimazole
4. Possible side effects
5. How to store Carbimazole
6. Contents of the pack and other information
Carbimazole is a sulfur-containing imidazole derivative which belongs to a group of medicines called anti-thyroid agents. Carbimazole is used to reduce the formation of thyroid hormones in adults and children with an over active thyroid gland. The condition is called hyperthyroidism. Carbimazole is also used in more serious cases, for example, to restore the normal function of the thyroid before its partial removal by surgery. It may also be used together with other treatments for hyperthyroidism like therapy prior to and post radio-iodine treatment.
Talk to your doctor or pharmacist before taking Carbimazole
If you are not sure if the above applies to you, talk to your doctor or pharmacist before taking Carbimazole.
Do not give this medicine to children under the age of two years because it may not be safe or effective.
Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines. This includes medicines obtained without a prescription, including herbal medicines. This is because Carbimazole can affect the way some medicines work. Also, some medicines can affect the way Carbimazole works.
In particular tell your doctor or pharmacist if you are taking any of the following:
If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice straight away before taking this medicine.
Pregnancy
Carbimazole can cause harm to an unborn baby. If you could get pregnant, use reliable contraception from the time you start treatment and during treatment. However, to reduce the possibility of any effects on your baby:
Your treatment with Carbimazole may need to be continued during pregnancy if the potential benefit outweighs the potential risk to you and your unborn baby.
Breast-feeding
You should not breast-feed if you are using Carbimazole. This is because small amounts may pass into the mother’s milk.
Ask your doctor or pharmacist for advice before taking any medicine.
You can drive when taking Carbimazole, but do not drive until you know how it affects you.
Carbimazole tablets contain lactose monohydrate. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicinal product.
This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially ‘sodium-free’.
Always take this medicine exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure.
The recommended starting dose is one to three 20 mg tablets, or four to twelve 5 mg tablets daily. Once control is achieved your doctor will gradually reduce your dose to one to three 5 mg tablets each day.
The recommended starting dose is three 5 mg tablets daily.
The score line is only there to help you break the tablet if you have difficulty swallowing it whole.
The dosage will be decided by your doctor according to your individual needs, and may be changed at intervals during treatment.
Do not change the dosage without consulting your doctor first.
Your doctor may decide to add an additional tablet (I-thyroxine), to help control your condition.
Some improvement is usually felt within one to three weeks. However, full beneficial effects usually take four to eight weeks.
In order to maintain control of the thyroid gland, you may need to continue to take Carbimazole tablets for several months. Your doctor will decide when treatment can be stopped. They may ask you to have occasional blood tests to help them to determine how you are responding to treatment.
Radio-iodine is another treatment for hyperthyroidism. If you need radioiodine treatment, your doctor will tell you to stop taking Carbimazole temporarily.
If you take more Carbimazole than you should, contact your doctor or nearest hospital emergency department immediately. Take the container and any remaining tablets with you.
If you forget to take Carbimazole take the next dose as soon as you remember. If your next dose is due, take both doses together.
If you have any further questions of the use of this medicine ask your doctor or pharmacist.
Like all medicines, this medicine can cause side effects, although not everybody gets them.
If you have an allergic reaction, stop taking Carbimazole and see a doctor straight away. The signs may include: sudden rash, swelling or difficulty in breathing.
Stop taking Carbimazole and see a doctor straight away if you notice any of the following side effects:
In addition, if you experience any of these symptoms while taking Carbimazole you should also contact your doctor immediately:
These could be signs of muscle problems, jaundice or inflammation of the liver and under medical supervision your doctor may want you to stop taking the medicine and carry out some blood tests on you.
Do not stop taking Carbimazole until you have consulted your doctor.
Carbimazole can sometimes cause bone marrow depression which causes a reduction in number of blood cells and reduces the ability to fight against infection. If it is not treated as soon as it is detected the condition can become life-threatening. Your doctor should carry out tests to check for bone marrow depression before restarting your treatment.
The following side effects are reported with a not known frequency (frequency cannot be estimated from the available data):
If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via Yellow Card Scheme, Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects, you can help provide more information on the safety of this medicine.
Keep this medicine out of the sight and reach of children.
Do not use this medicine after the expiry date which is stated on the label, carton and blister after EXP. The expiry date refers to the last day of that month.
Store below 25°C.
Do not use this medicine if you notice any change in the appearance of the tablets.
Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help to protect the environment.
Carbimazole 5 mg tablets
Pink colored, mottled, uncoated, circular [diameter 5 mm], biconvex tablets debossed with “C5” on one side “break line” on other side. The score line is only to facilitate breaking for ease of swallowing and not to divide into equal doses.
Carbimazole 20 mg tablets
Pink colored, mottled, uncoated, circular [diameter 8.3 mm], biconvex tablets debossed with “C 20” on one side and “break line” on other side. The score line is only to facilitate breaking for ease of swallowing and not to divide into equal doses.
Carbimazole tablets are available in blister packs.
Pack sizes
Blister packs: 100 tablets.
or
or
This leaflet was last revised in 10/2025.
P1540071
Milpharm Limited, 1 Roundwood Avenue, Stockley Park, Uxbridge, UB11 1AF, UK
+ 44 (0)208 845 8811
+44 (0)208 845 8811
http://www.aurobindo.com
+44 (0)208 845 8795