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Carbimazole is a pro-drug that is converted to methimazole in the body.

Last Modified: 22 May 2024

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What is Carbimazole? 

Carbimazole is an anti-thyroid pro-drug that is converted to methimazole in the body, which then acts to reduce the production of thyroid hormones.

Carbimazole is synthesized chemically and has a thiourea structure. It works by interfering with the use of iodine in the thyroid gland. 

Global Name

Generic Names: Carbimazole  


Brand names 

Some brand names under which Carbimazole is marketed: 

  • Neo-Mercazole: Commonly used in various countries including India. 
  • Vidalta: A prolonged-release formulation used in veterinary medicine for cats. 
  • Carbimazol Henning: A brand name used in some European countries. 



What is Carbimazole used for?

Carbimazole is primarily used to treat hyperthyroidism, a condition where the thyroid gland produces too much thyroid hormone. 

How Do You Use Carbimazole? 

Carbimazole is available in tablet form.  

Dosage information (guided by target thyroid hormone levels in the body): 

  • The initial dose for adults may range from 20-60 mg per day. 
  • The maintenance dose is typically reduced to 5-15 mg per day. 
  • Children's dosage should be determined by a paediatrician.  

Is there anyone who can’t take Carbimazole

Use in children requires supervision; adults with severe liver disorders should avoid it; elderly may use it cautiously; and it's not recommended during pregnancy and lactation unless deemed necessary under medical supervision.


Warnings and precautions: 

Patients should report any signs of infection or unusual bruising, which could indicate a blood disorder. Carbimazole should be taken with food to minimize gastrointestinal upset.

Individuals allergic to carbimazole or methimazole should not take this medication. 

Drug Interactions and contraindications of the drug 

Carbimazole can interact with blood thinners, digoxin, and theophylline. It is contraindicated in those with a history of severe blood disorders (e.g. agranulocytosis). 

Side Effects

Common side effects include gastrointestinal upset, headache, and itching. Serious side effects may include agranulocytosis and liver problems. 

Pharmacist Tips

  • Starting Carbimazole: Follow the doctor’s prescription closely, as dosages may change over the treatment period. 
  • Missed Dose: If a dose is missed, take it as soon as you remember. If it's close to the next dose, skip it. Do not double up. 
  • Alcohol Consumption: Discuss with your healthcare provider as alcohol can affect thyroid function and medication metabolism. 
  • Storage Information: Store in a cool, dry place away from light and moisture. 
  • Regular Checkups: Frequent blood tests are required to monitor thyroid function and side effects. 
  • Adherence to Therapy: It's essential to continue taking Carbimazole for the duration prescribed, even after symptoms improve, to ensure proper management of thyroid levels. 
  • Diet Considerations: There are no specific dietary restrictions, but a balanced diet supports overall health.


Where is Carbimazole available in Hong Kong?

Carbimazole is a prescription medication that can be prescribed by healthcare providers.


What is Carbimazole used for?  

Carbimazole is a medication primarily used to treat hyperthyroidism,  a condition where the thyroid gland is hyperactive and produces too much thyroid hormone. 

How is Carbimazole 5mg taken?  

To take Carbimazole 5mg, follow your doctor's prescription closely; typically, it's taken orally with or without food, and at regular intervals to maintain stable blood levels of the medication. 

How to avoid weight gain on Carbimazole?    

To avoid weight gain while on Carbimazole, consider the following tips: 

  1. Maintain a balanced diet: Focus on a diet rich in fruits, vegetables, whole grains, and lean proteins. Monitor your calorie intake to avoid consuming more than you burn. 
  1. Regular exercise: Incorporate regular physical activity into your routine to boost metabolism and burn calories. 
  1. Monitor thyroid levels: Work with your healthcare provider to keep your thyroid hormone levels within the target range. Both hyperthyroidism and hypothyroidism can affect your weight. 
  1. Stay hydrated: Drink plenty of water throughout the day, which can help with satiety and overall metabolism. 
  1. Limit sugary and processed foods: These can contribute to weight gain and provide little nutritional value. 

This website provides content related to drug use and medicine for informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Do not use the information on this website to diagnose or treat a health problem or disease without consulting a qualified healthcare provider. The website's owners and contributors are not liable for any repercussions, adverse effects, or consequences resulting from the use of any medication or information provided herein.

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