What is the recommended dosage for propylthiouracil (PTU)?

From the Guidelines

The recommended dosage of propylthiouracil (PTU) typically starts at 100-150 mg three times daily (300-450 mg total daily) for adults with hyperthyroidism. After achieving a euthyroid state (usually within 6-8 weeks), the dose can be gradually reduced to a maintenance dose of 50-150 mg daily. For severe hyperthyroidism or thyroid storm, higher initial doses of 200-400 mg every 4-6 hours may be necessary. Children's dosing is weight-based, usually 5-7 mg/kg/day divided into three doses. Pregnant women often require lower doses, typically 100-150 mg daily, with dose adjustments based on thyroid function tests. PTU works by inhibiting thyroid hormone synthesis by blocking the enzyme thyroid peroxidase and preventing peripheral conversion of T4 to T3. Regular monitoring of thyroid function tests is essential to adjust dosing appropriately. Patients should be aware that PTU can cause serious liver injury, so any signs of liver problems (jaundice, abdominal pain, dark urine) require immediate medical attention. Taking the medication with food can help reduce gastrointestinal side effects 1.

Some key points to consider when prescribing PTU include:

• Monitoring for signs of liver injury, such as jaundice, abdominal pain, and dark urine
• Adjusting the dose based on thyroid function tests to avoid over- or under-treatment
• Being aware of the potential for agranulocytosis, a rare but serious side effect of PTU
• Considering alternative treatments for patients with severe renal impairment or other contraindications to PTU.

It's also important to note that the evidence for PTU dosing is largely based on clinical experience and expert opinion, rather than randomized controlled trials 1. Therefore, the dosing recommendations may vary depending on the specific clinical context and patient population.

In terms of specific dosing regimens, the following may be considered:

• Initial dose: 100-150 mg three times daily (300-450 mg total daily)
• Maintenance dose: 50-150 mg daily
• Severe hyperthyroidism or thyroid storm: 200-400 mg every 4-6 hours
• Children: 5-7 mg/kg/day divided into three doses
• Pregnant women: 100-150 mg daily, with dose adjustments based on thyroid function tests.

Overall, the key to successful treatment with PTU is careful monitoring and adjustment of the dose to achieve a euthyroid state while minimizing the risk of adverse effects 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Propylthiouracil is administered orally. The total daily dosage is usually given in 3 equal doses at approximately 8-hour intervals. Adults The initial dose is 300 mg daily. In patients with severe hyperthyroidism, very large goiters, or both, the initial dose may be increased to 400 mg daily; an occasional patient will require 600 to 900 mg daily initially The usual maintenance dose is 100 to 150 mg daily. The recommended dosage for propylthiouracil (PTU) is:

• Initial dose: 300 mg daily for adults, which can be increased to 400 mg daily for severe cases
• Maintenance dose: 100 to 150 mg daily for adults
• Pediatric patients: 50 mg daily for patients 6 years or older, with careful upward titration based on clinical response and evaluation of TSH and free T4 levels 2

From the Research

Dosage Information for Propylthiouracil

• The recommended dosage for propylthiouracil (PTU) is not explicitly stated in the provided studies 3, 4, 5, 6, 7.
• However, it is mentioned that PTU is used in the treatment of hyperthyroidism, particularly in patients with Graves' disease 4, 6.
• The studies discuss the efficacy and side effects of PTU, but do not provide specific dosage information 3, 5, 6.
• One study mentions that patients who experience side effects with methimazole can be switched to PTU and vice versa 6.
• Another study discusses the use of PTU in pregnant women and nursing mothers, but does not provide dosage information 6.
• The treatment options for hyperthyroidism, including PTU, are discussed in a review article, but dosage information is not provided 7.

Administration and Usage

• PTU is used in the treatment of hyperthyroidism, particularly in patients with Graves' disease 4, 6.
• The drug can be used in combination with other medications, such as beta-blockers and glucocorticoids, to control hyperthyroidism 4.
• PTU is recommended for use in pregnant women and nursing mothers due to its relatively low placental transfer and safety profile 6.
• The drug can be used as an alternative to methimazole in patients who experience side effects or have contraindications to methimazole 6.

Side Effects and Contraindications

• PTU can cause side effects, including agranulocytosis, vasculitis, and rash 4, 5.
• The drug can also cause immunologic effects, such as the development of autoantibodies 5.
• Patients who experience side effects or have contraindications to PTU may need to be switched to alternative treatments, such as methimazole or radioactive iodine ablation 4, 7.