Propylthiouracil
Propylthiouracil (PTU) is an antithyroid agent that inhibits the synthesis of thyroid hormones by interfering with thyroid peroxidase. It also inhibits the peripheral conversion of T4 to T3. Due to the risk of severe liver injury and acute liver failure, it is generally reserved for patients who cannot tolerate methimazole, or during the first trimester of pregnancy when methimazole is contraindicated.
Dosage by Body Weight
The standard adult initial dose is 300 mg daily, administered in 3 divided doses at approximately 8-hour intervals. In patients with severe hyperthyroidism, initial doses of 400 mg to 900 mg daily may be required. Maintenance dosage is usually 100 mg to 150 mg daily. Pediatric dosing is typically calculated by body weight (initially 5 to 7 mg/kg/day in 3 divided doses). Take consistently with or without food.
- Body Weight
- Below 5 kg
- Dose
- Not routine
- Frequency
- Use only if prescribed
- Tracking Notes
- Requires strict supervision by a pediatric endocrinologist due to risk of severe hepatotoxicity.
- Body Weight
- 5-7 kg
- Dose
- 10 mg to 15 mg
- Frequency
- Three times daily (every 8 hours)
- Tracking Notes
- Based on 5-7 mg/kg/day initial pediatric dosing. Monitor thyroid function closely.
- Body Weight
- 8-10 kg
- Dose
- 15 mg to 20 mg
- Frequency
- Three times daily (every 8 hours)
- Tracking Notes
- Adjust dose according to free T4 and TSH levels.
- Body Weight
- 11-15 kg
- Dose
- 20 mg to 30 mg
- Frequency
- Three times daily (every 8 hours)
- Tracking Notes
- Maintenance dose should be reduced to the lowest effective amount once euthyroid.
- Body Weight
- 16-20 kg
- Dose
- 30 mg to 40 mg
- Frequency
- Three times daily (every 8 hours)
- Tracking Notes
- Monitor for signs of agranulocytosis (fever, sore throat) and liver dysfunction.
| Body Weight | Dose | Frequency | Tracking Notes |
|---|---|---|---|
| Below 5 kg | Not routine | Use only if prescribed | Requires strict supervision by a pediatric endocrinologist due to risk of severe hepatotoxicity. |
| 5-7 kg | 10 mg to 15 mg | Three times daily (every 8 hours) | Based on 5-7 mg/kg/day initial pediatric dosing. Monitor thyroid function closely. |
| 8-10 kg | 15 mg to 20 mg | Three times daily (every 8 hours) | Adjust dose according to free T4 and TSH levels. |
| 11-15 kg | 20 mg to 30 mg | Three times daily (every 8 hours) | Maintenance dose should be reduced to the lowest effective amount once euthyroid. |
| 16-20 kg | 30 mg to 40 mg | Three times daily (every 8 hours) | Monitor for signs of agranulocytosis (fever, sore throat) and liver dysfunction. |
Formulation
Purpose
Treatment of hyperthyroidism, Graves' disease, toxic multinodular goiter, and thyroid storm.
Generic Name
PropylthiouracilBranded Drug Names
Propylthiouracil 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.