Medicines & treatments centre

CARBIMAZOLE WARNINGS

Carbimazole should be used with caution in: the elderly, people with mild to moderate liver disease, pregnant women, people with swelling of the thyroid gland (goitre).

It should not be used in:

• Patients with an allergy to carbimazole or to any other ingredients in the medicine or to other anti-thyroid drugs including propylthiouracil, people with severe liver disease, people with serious blood disorders, women who are breastfeeding, patients who are unable to tolerate galactose, people who have too little of the lactase enzyme or are unable to absorb glucose or galactose.

Also see list of precautions and interactions

STORAGE

No special storage requirements.

CARBIMAZOLE USES

What is it used for?

• Carbimazole is used to reduce the production of a hormone called thyroxine by the thyroid gland.
• It is a thioamide, sometimes known as an anti-thyroid drug.
• It is used to treat and manage an overactive thyroid gland (hyperthyroidism).
• In general this drug is used to treat and manage an overactive thyroid gland (hyperthyroidism).
• Benefits of being on this drug can include relief from the symptoms of an overactive thyroid which include restlessness, tremor of the hands, weight loss, irregular heart beat (palpitations), sweating, shortness of breath, tiredness and skin problems.

Listed below are the typical uses of carbimazole.

• Overactive thyroid gland (hyperthyroidism)

On occasion your doctor may prescribe this medicine to treat a condition not on the above list. Such conditions are listed below.

• To restore the normal function of the thyroid before its partial removal by surgery
• Before and after radio-iodine treatment

HOW TO USE/TAKE

How often do I take it?

• Take this medication orally, swallowed with some water, with or without food. After you have been on your medicine for a while your doctor may decrease your dose so that you are taking your medicine just once a day.
• Use this medication regularly in order to get the most benefit from it.
• Remember to use it at the same time each day - unless specifically told otherwise by your doctor.
• It may take up to 4 to 8 weeks before the full benefit of this drug takes effect.
• Certain medical conditions may require different dosage instructions as directed by your doctor.

What dose?

• Dosage is based on your age, gender, medical condition, response to therapy, and use of certain interacting medicines.

Do I need to avoid anything?

• The effect of carbimazole on a patient's ability to drive or operate machinery is not known. Consult your doctor or pharmacist for more details.

When can I stop?

• It is important to continue taking this medication even if you feel well, unless your doctor tells you to stop.

CARBIMAZOLE SIDE EFFECTS

• Feeling sick
• Headache
• Dizziness
• Skin rashes
• Itching
• Bruising
• Stomach upset
• Painful joints
• Hair thinning
• Taste disturbances
• Liver problems (jaundice)
• Blood disorders
• Muscle pain
• Fever
• Hair loss
• Cutaneous vasculitis (inflammation of the blood vessels in the skin)
• Swelling (angioedema)
• Bleeding

If any of these persist or you consider them severe then inform your doctor or pharmacist.

Stop taking your tablets and tell your doctor immediately if you develop any of the following symptoms:

• Sore throat, mouth ulcers, bruising or bleeding, fever and feeling generally unwell which may be a sign of a blood disorder.
• Pain in the upper abdomen, weight loss and general itching (pruritus) which may be a sign of liver problems.
• You think you have an infection.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

The Yellow Card Scheme allows you to report suspected side effects from any type of medicine (which includes vaccines, herbals and over the counter medicines) that you are taking. It is run by the medicines safety watchdog called the Medicines and Healthcare products Regulatory agency (MHRA). Please report any suspected side effect on the Yellow Card Scheme website.

CARBIMAZOLE PRECAUTIONS

Before taking carbimazole, tell your doctor or pharmacist if you are allergic to it; or to other anti-thyroid drugs; or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: an allergy to carbimazole or to any other ingredients in the medicine or to other anti-thyroid drugs including propylthiouracil, severe liver disease, serious blood disorders, are unable to tolerate galactose, have too little of the lactase enzyme or are unable to absorb glucose or galactose, you are breastfeeding.

Before using this medication, tell your doctor or pharmacist your medical history, especially any of the following mild to moderate liver disease, swelling of the thyroid gland (goitre), you are pregnant.

Before having surgery, tell your doctor or dentist that you are taking this medication.

Does alcohol intake affect this drug?

• Alcohol intake is not known to affect carbimazole.

The elderly: carbimazole should be used with caution in the elderly as it may be associated with a higher risk of fatal blood disorders in the elderly.

Pregnancy and breastfeeding - please ensure you read the detailed information below

PREGNANCY

Carbimazole is suitable for doctors to consider prescribing during pregnancy. However, very rare cases of birth defects have been observed following the use of carbimazole and therefore its use should be based on an individual risk/benefit assessment.

It is sensible to limit use of medication during pregnancy whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.

BREAST FEEDING

Carbimazole is not safe to take if you are breastfeeding.

It is sensible to limit use of medication during breastfeeding whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.

CARBIMAZOLE INTERACTIONS

Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with them first.

This drug should not be used with the following medications because very serious, possibly fatal interactions may occur:

• None known.

Before using this medication, tell your doctor or pharmacist of all prescription and non-prescription/herbal products you may use, especially of:

• Drugs that thin the blood such as warfarin
• Theophylline

This information does not contain all possible interactions. Therefore, before using carbimazole, tell your doctor or pharmacist of all the products you use.

CARBIMAZOLE OVERDOSE

If you or someone near to you has taken more carbimazole tablets than was prescribed, contact your doctor or go to the nearest hospital emergency department immediately. Remember to take any remaining tablets and the tablet container or patient information leaflet with you so the doctors know what has been taken.

If you think you, or someone you care for, might have accidentally taken more than the recommended dose of carbimazole or intentional overdose is suspected, contact your local hospital, GP or if in the UK call NHS Direct on 0845 4647.

MISSED DOSE

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.