What are the treatment options for hyperthyroidism?

Treatment for Hyperthyroidism

For most patients with hyperthyroidism, initiate treatment with methimazole as the antithyroid medication of choice, combined with beta-blockers for immediate symptom control, reserving propylthiouracil specifically for first-trimester pregnancy or methimazole intolerance. 1, 2

Initial Symptomatic Management

• Beta-blockers (propranolol or atenolol) should be started immediately for symptomatic relief of tachycardia, tremor, and other adrenergic symptoms while waiting for antithyroid medications to take effect 1, 2
• Beta-blockers are particularly critical for patients with cardiac symptoms and provide rapid symptom control within hours to days 2

Primary Pharmacological Treatment

First-Line Antithyroid Drug Selection

• Methimazole is the preferred antithyroid drug for the vast majority of patients due to its superior efficacy, once-daily dosing, lower cost, and fewer major side effects 3, 4
• Starting dose of methimazole is typically 10-30 mg as a single daily dose 5
• Methimazole achieves more rapid normalization of thyroid hormones compared to propylthiouracil, with significantly lower T3 and T4 levels by 4 weeks of treatment 6, 7

When to Use Propylthiouracil

• Propylthiouracil is indicated only for patients intolerant to methimazole or when surgery/radioactive iodine is not appropriate 8
• During first-trimester pregnancy, propylthiouracil is preferred due to lower risk of congenital anomalies (methimazole is associated with aplasia cutis and choanal/esophageal atresia), though methimazole can be used after the first trimester 1, 5
• Propylthiouracil dosing is 100-300 mg every 6 hours, requiring multiple daily doses 5

Definitive Treatment Options

Radioactive Iodine Therapy

• Radioactive iodine (¹³¹I) is a definitive treatment option, particularly for toxic nodular goiter 4
• Radioactive iodine is absolutely contraindicated during pregnancy 1, 2
• Patients typically develop hypothyroidism after radioactive iodine therapy, requiring lifelong thyroid hormone replacement 2
• Can be used as definitive therapy after initial stabilization with antithyroid drugs 9

Surgical Management

• Near-total or total thyroidectomy is recommended for patients with large goiters, suspicious nodules, or severe ophthalmopathy 2
• Surgery is indicated for patients who have failed or are intolerant to medical therapy 1
• Thyroidectomy should be reserved for pregnant women who do not respond to thioamide therapy 1
• Requires lifelong thyroid hormone replacement post-surgery 2

Treatment Duration and Recurrence

• Standard antithyroid drug courses last 12-18 months, but recurrence occurs in approximately 50% of patients 4
• Long-term treatment with antithyroid drugs (5-10 years) is associated with fewer recurrences (15%) compared to short-term treatment 4
• Risk factors for recurrence include: age younger than 40 years, FT4 ≥40 pmol/L, TSH-binding inhibitory immunoglobulins >6 U/L, and goiter size ≥WHO grade 2 4

Monitoring Requirements

• Monitor thyroid function tests every 4-6 weeks initially, with dose adjustments based on clinical response and laboratory values 2
• Patients on antithyroid medications require regular monitoring for serious side effects: agranulocytosis, hepatitis, vasculitis, and thrombocytopenia 1
• Monitor for transition from hyperthyroidism to hypothyroidism, especially in thyroiditis cases 1
• Long-term follow-up is necessary even after successful treatment due to risk of recurrence or development of hypothyroidism 2

Management of Severe Hyperthyroidism

• Severe hyperthyroidism or thyroid storm requires hospitalization with aggressive management including beta-blockers, high-dose antithyroid drugs, hydration, and supportive care 1, 2
• In cases of immune checkpoint inhibitor-induced hyperthyroidism, hold the offending agent until symptoms resolve and obtain mandatory endocrine consultation 1

Special Considerations for Thyroiditis

• Thyroiditis-related hyperthyroidism typically does not require antithyroid drugs, as it represents destructive thyrotoxicosis rather than true hyperthyroidism 9
• Treatment focuses on symptom management with beta-blockers and close monitoring for transition to hypothyroidism 2
• Steroids are reserved only for severe cases of destructive thyrotoxicosis 4