From the FDA Drug Label
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 initial treatment for a patient with severe hyperthyroidism is propylthiouracil (PO) with a dose of 300 mg daily, which may be increased to 400 mg daily or more in some cases 1.
- The dose may be adjusted based on clinical response and evaluation of TSH and free T4 levels.
- It is essential to monitor patients closely, especially when using high doses, due to the risk of severe liver injury.
From the Research
The initial treatment for a patient with severe hyperthyroidism typically involves a combination of beta-blockers and antithyroid medications, with methimazole being the preferred antithyroid medication due to its efficacy and safety profile, as supported by the most recent study 2. The treatment approach should prioritize controlling adrenergic symptoms and reducing thyroid hormone production.
- Beta-blockers such as propranolol (40-80 mg every 6-8 hours) or other beta-blockers should be started immediately to control symptoms like tachycardia, tremor, and anxiety.
- Antithyroid medications such as methimazole (starting at 20-40 mg daily in divided doses) should be initiated to block new thyroid hormone synthesis.
- Supportive measures include adequate hydration, nutritional support, and treatment of precipitating factors. In cases of thyroid storm (life-threatening hyperthyroidism), additional treatments include corticosteroids (e.g., hydrocortisone 100 mg IV every 8 hours), cooling measures for hyperthermia, and potentially cholestyramine to reduce enterohepatic circulation of thyroid hormones, as discussed in 2 and 3. The choice of treatment should be individualized and patient-centered, taking into account the underlying diagnosis, severity of hyperthyroidism, and patient preferences, as recommended in 2. It is essential to note that propylthiouracil (PTU) is preferred in the first trimester of pregnancy and thyroid storm due to its additional ability to block peripheral T4 to T3 conversion, but methimazole is generally the preferred antithyroid medication due to its efficacy and safety profile, as supported by 3.