Tapazole
Tapazole (methimazole) is an antithyroid drug that inhibits the synthesis of thyroid hormones. It does not inactiviate existing thyroxine and triiodothyronine stored in the colloid or circulating in the blood, nor does it interfere with the effectiveness of thyroid hormones given by mouth or injection.
Dosage by Body Weight
Adult starting dose is typically 15 mg to 60 mg daily divided into 3 doses every 8 hours. Pediatric dosing is calculated by body weight (typically 0.4 mg/kg/day in 3 divided doses). Maintenance dose is usually half of the initial starting dose once euthyroid is achieved.
- Body Weight
- Below 5 kg
- Dose
- 0.5 mg to 1.5 mg daily
- Frequency
- Divided into 3 doses (every 8 hours)
- Tracking Notes
- Use only under strict specialist pediatric supervision. Monitor thyroid function closely.
- Body Weight
- 5-7 kg
- Dose
- 1.5 mg to 2.5 mg daily
- Frequency
- Divided into 3 doses (every 8 hours)
- Tracking Notes
- Adjust dose based on clinical response and thyroid hormone levels.
- Body Weight
- 8-10 kg
- Dose
- 3 mg to 4 mg daily
- Frequency
- Divided into 3 doses (every 8 hours)
- Tracking Notes
- Monitor complete blood count (CBC) for risk of agranulocytosis.
- Body Weight
- 11-15 kg
- Dose
- 4 mg to 6 mg daily
- Frequency
- Divided into 3 doses (every 8 hours)
- Tracking Notes
- Administer consistently with or without food to maintain stable absorption.
- Body Weight
- 16-20 kg
- Dose
- 6 mg to 8 mg daily
- Frequency
- Divided into 3 doses (every 8 hours)
- Tracking Notes
- Titrate down to maintenance dose (approximately half) once euthyroid state is reached.
| Body Weight | Dose | Frequency | Tracking Notes |
|---|---|---|---|
| Below 5 kg | 0.5 mg to 1.5 mg daily | Divided into 3 doses (every 8 hours) | Use only under strict specialist pediatric supervision. Monitor thyroid function closely. |
| 5-7 kg | 1.5 mg to 2.5 mg daily | Divided into 3 doses (every 8 hours) | Adjust dose based on clinical response and thyroid hormone levels. |
| 8-10 kg | 3 mg to 4 mg daily | Divided into 3 doses (every 8 hours) | Monitor complete blood count (CBC) for risk of agranulocytosis. |
| 11-15 kg | 4 mg to 6 mg daily | Divided into 3 doses (every 8 hours) | Administer consistently with or without food to maintain stable absorption. |
| 16-20 kg | 6 mg to 8 mg daily | Divided into 3 doses (every 8 hours) | Titrate down to maintenance dose (approximately half) once euthyroid state is reached. |
Formulation
Purpose
Treatment of hyperthyroidism (overactive thyroid), thyroid storm, and preparation for thyroidectomy or radioactive iodine therapy.
Generic Name
MethimazoleScheduled Drug
Yes. This medicine should be supplied or used only according to applicable prescription and regulatory requirements.