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Propylthiouracil Dosage

Medically reviewed by Drugs.com. Last updated on Oct 27, 2020.

Applies to the following strengths: 50 mg

Usual Adult Dose for Hyperthyroidism

Initial dose: 100 mg orally every 8 hours
Maintenance dose: 100 to 150 mg orally daily administered in 3 equally divided doses approximately every 8 hours

Comments:
-For patients with severe hyperthyroidism, very large goiters, or both, the initial dose may be increased to 400 mg, or for the occasional patient, up to 600 to 900 mg daily initially (administered in 3 equally divided doses as approximately 8-hour intervals).

Uses:
-For patients with Graves' disease and hyperthyroidism or toxic multinodular goiter who are intolerant of methimazole and for whom surgery or radioactive iodine therapy is not an appropriate treatment option.
-To ameliorate symptoms of hyperthyroidism in preparation for thyroidectomy or radioactive iodine therapy in patients who are intolerant of methimazole.

Usual Adult Dose for Thyroid Storm

Initial dose: 100 mg orally every 8 hours
Maintenance dose: 100 to 150 mg orally daily administered in 3 equally divided doses approximately every 8 hours

Comments:
-For patients with severe hyperthyroidism, very large goiters, or both, the initial dose may be increased to 400 mg, or for the occasional patient, up to 600 to 900 mg daily initially (administered in 3 equally divided doses as approximately 8-hour intervals).

Uses:
-For patients with Graves' disease and hyperthyroidism or toxic multinodular goiter who are intolerant of methimazole and for whom surgery or radioactive iodine therapy is not an appropriate treatment option.
-To ameliorate symptoms of hyperthyroidism in preparation for thyroidectomy or radioactive iodine therapy in patients who are intolerant of methimazole.

Usual Pediatric Dose for Hyperthyroidism

6 years or older:
Initial dose: 50 mg orally daily in 3 equally divided doses approximately every 8 hours
-Carefully titrate based on clinical response and evaluation of TSH and free T4 levels

OR,
6 to 10 years of age:
Initial dose: 50 to 150 mg orally daily in 3 equally divided doses approximately every 8 hours
10 years or older:
Initial dose: 150 to 300 mg orally daily in 3 equally divided doses approximately every 8 hours

Maintenance dose: 50 mg orally twice a day when euthyroid

Comments:
-This drug is not recommended for use in pediatric patients except in rare instances when other therapies are not an option.
-Dose studies have not been conducted in the pediatric population, the above dose recommendations are suggested from clinical practice.
-Although cases of severe liver injury have been reported with doses as low as 50 mg per day, most cases were associated with doses of 300 mg per day and higher.

Use: For the treatment of hyperthyroidism in pediatric patients when, in rare instances other therapies are not an option.

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Dose Adjustments

Elderly: Dose selection should be cautious, reflecting the greater frequency of decreased hepatic, renal, cardiac function, and concomitant disease or other drug therapy.

Precautions

US BOXED WARNINGS:
-Severe liver injury and acute liver failure, in some cases fatal, have been reported in patients treated with this drug. These reports of hepatic reactions include cases requiring liver transplantation in adult and pediatric patients.
-This drug should be reserved for patients who cannot tolerate methimazole and in whom radioactive iodine therapy or surgery are not appropriate treatments for the management of hyperthyroidism.
-This drug may be the treatment of choice when an antithyroid drug is indicated during or just prior to the first trimester of pregnancy.

Safety and efficacy have not been established in patients younger than 6 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:
-Take orally in equally divided doses at approximately 8-hour intervals

Missed dose: If a dose is missed, take it as soon as you remember; if it is almost time for your next dose, skip the missed dose. Do not double your dose.

General:
-Patients treated with this drug should be under close surveillance due to the potential for serious adverse effects.
-In general, this drug should only be considered in patients who are intolerant of methimazole and for whom surgery or radioactive iodine therapy is not an appropriate treatment option.
-It may be the treatment of choice for the first trimester of pregnancy due to methimazole use being associated with fetal abnormalities; after the first trimester it may be preferable to switch to methimazole.

Monitoring:
-Routine monitoring of TSH and free T4 levels is necessary to avoid under or over treatment
-Consider monitoring prothrombin time if there are concerns of bleeding; prothrombin time should be monitored before surgical procedures
-Monitor blood counts if there are signs and symptoms of agranulocytosis
-Routine liver function testing may not attenuate the risk of severe liver injury; however, immediately perform liver function testing if there are any symptoms of hepatic dysfunction

Patient advice:
-Patient should be instructed to read the US FDA-approved patient labeling (Medication Guide)
-Patients should understand the importance of contacting their healthcare provider promptly if they experience any signs or symptoms of liver dysfunction, low blood counts, bleeding, or vasculitis.
-Women should be instructed to speak to their healthcare provider if they are pregnant or plan to become pregnant.
-This drug may cause dizziness, drowsiness, or sleepiness; do not drive or perform hazardous tasks until you know how this drug affects you.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.