Carbimazole
Carbimazole is an antithyroid agent and a prodrug that is rapidly converted into its active metabolite, methimazole, after absorption. It works by inhibiting the thyroid peroxidase enzyme, which prevents the iodination of tyrosine residues in thyroglobulin, thereby reducing the synthesis of thyroid hormones T3 and T4.
Dosage by Body Weight
Carbimazole is taken orally, with or without food. Adult starting doses typically range from 15 mg to 40 mg daily (sometimes up to 60 mg in severe cases), taken as a single dose or divided into smaller doses, until the patient becomes euthyroid. The dose is then gradually reduced to a maintenance level of 5 mg to 15 mg daily. Pediatric doses are determined based on age, body weight, and clinical assessment under strict specialist guidance.
- Body Weight
- Below 5 kg
- Dose
- Not routine / 1.25 mg to 2.5 mg daily
- Frequency
- Once daily or divided
- Tracking Notes
- Must be initiated and monitored strictly by a pediatric endocrinologist.
- Body Weight
- 5-7 kg
- Dose
- 2.5 mg to 5 mg daily
- Frequency
- Once daily or divided
- Tracking Notes
- Dose is adjusted based on thyroid function test (TFT) results and clinical response.
- Body Weight
- 8-10 kg
- Dose
- 5 mg daily
- Frequency
- Once daily or divided
- Tracking Notes
- Parents should be warned to report any fever, sore throat, or mouth ulcers immediately due to the risk of neutropenia.
- Body Weight
- 11-15 kg
- Dose
- 5 mg to 7.5 mg daily
- Frequency
- Once daily or split into two doses
- Tracking Notes
- Routine monitoring of complete blood count and thyroid panel is essential.
- Body Weight
- 16-20 kg
- Dose
- 7.5 mg to 10 mg daily
- Frequency
- Once daily or split into two doses
- Tracking Notes
- Administer with caution. Adjust to the lowest effective maintenance dose as soon as euthyroidism is achieved.
| Body Weight | Dose | Frequency | Tracking Notes |
|---|---|---|---|
| Below 5 kg | Not routine / 1.25 mg to 2.5 mg daily | Once daily or divided | Must be initiated and monitored strictly by a pediatric endocrinologist. |
| 5-7 kg | 2.5 mg to 5 mg daily | Once daily or divided | Dose is adjusted based on thyroid function test (TFT) results and clinical response. |
| 8-10 kg | 5 mg daily | Once daily or divided | Parents should be warned to report any fever, sore throat, or mouth ulcers immediately due to the risk of neutropenia. |
| 11-15 kg | 5 mg to 7.5 mg daily | Once daily or split into two doses | Routine monitoring of complete blood count and thyroid panel is essential. |
| 16-20 kg | 7.5 mg to 10 mg daily | Once daily or split into two doses | Administer with caution. Adjust to the lowest effective maintenance dose as soon as euthyroidism is achieved. |
Formulation
Purpose
Used to treat hyperthyroidism (an overactive thyroid gland). It helps reduce the production of thyroid hormones. It is also used to prepare patients for thyroid surgery (thyroidectomy) or radioactive iodine treatment.
Generic Name
CarbimazoleBranded Drug Names
Carbimazole is listed as a generic drug name. Common branded medicines that may contain the same active ingredient include:
Scheduled Drug
Yes. This medicine should be supplied or used only according to applicable prescription and regulatory requirements.