What are the recommended treatments for hyperthyroidism?

Treatment Options for Hyperthyroidism

Beta-blockers are the first-line treatment for symptomatic hyperthyroidism, while definitive treatment should be chosen among antithyroid medications, radioactive iodine ablation, or surgical thyroidectomy based on the underlying cause and patient factors. 1, 2

Initial Management of Symptomatic Hyperthyroidism

• For symptomatic hyperthyroidism (usually grade 1 or 2):
  • Start beta-blocker therapy (propranolol or atenolol/metoprolol) to control symptoms 1
  • Consider temporarily interrupting immune checkpoint inhibitor therapy if applicable until patient becomes asymptomatic 1
  • Non-dihydropyridine calcium channel antagonists (diltiazem, verapamil) are alternatives when beta-blockers are contraindicated 1

Definitive Treatment Options

1. Antithyroid Medications

• Methimazole (MMI):

  • Preferred first-line antithyroid drug for most patients 3
  • Dosing recommendations:
    • Mild to moderate hyperthyroidism: 15 mg/day
    • Severe hyperthyroidism (FT4 ≥7 ng/dL): 30 mg/day 3
  • Lower risk of hepatotoxicity compared to propylthiouracil 3

• Propylthiouracil (PTU):

  • FDA WARNING: Severe liver injury and acute liver failure have been reported 4
  • Should be reserved for:
    • Patients who cannot tolerate methimazole
    • First trimester of pregnancy
    • Thyroid storm (due to additional T3→T4 conversion inhibition) 4, 2
  • Higher rate of adverse effects, especially mild hepatotoxicity 3

2. Radioactive Iodine (RAI) Ablation

• Most widely used definitive treatment in the United States 5
• Particularly effective for toxic nodular goiter 2
• Considerations:
  • Normalize thyroid function before treatment if possible 1
  • Be aware that thyroid hormone levels may transiently increase after RAI therapy 6
  • Contraindicated in pregnancy and breastfeeding 2

3. Surgical Thyroidectomy

• Indicated for:
  • Large goiters causing compressive symptoms
  • Suspicious thyroid nodules
  • Patients desiring rapid definitive treatment
  • Pregnant women who cannot tolerate antithyroid drugs 2, 7

Treatment Selection Based on Etiology

Graves' Disease (70% of cases)

• First-line: Antithyroid drugs (methimazole preferred)
  • 12-18 month course has ~50% recurrence rate
  • Long-term treatment (5-10 years) reduces recurrence to ~15% 2
• RAI or surgery for definitive treatment if recurrence occurs or preferred by patient 7

Toxic Nodular Goiter (16% of cases)

• RAI or thyroidectomy are preferred definitive treatments 2
• Radiofrequency ablation is an emerging alternative 2

Thyroiditis-Induced Hyperthyroidism (3%)

• Usually self-limiting and transient
• Symptomatic treatment with beta-blockers
• Steroids only in severe cases 2

Drug-Induced Hyperthyroidism (9%)

• Discontinue causative agent if possible (amiodarone, tyrosine kinase inhibitors, immune checkpoint inhibitors)
• Symptomatic treatment with beta-blockers 2

Monitoring and Follow-up

• Monitor thyroid function tests every 4-6 weeks until stable 8
• Once stable, check every 6-12 months 8
• For patients on antithyroid drugs, monitor for:
  • Liver dysfunction (anorexia, pruritus, jaundice, right upper quadrant pain)
  • Agranulocytosis (sore throat, fever, infection)
  • Vasculitis (rash, hematuria, dyspnea) 4

Special Considerations

• Pregnancy: PTU preferred in first trimester, then switch to methimazole 4
• Elderly patients: Start with lower doses of antithyroid drugs and beta-blockers; target higher TSH range (1.0-4.0 mIU/L) 8
• Cardiac patients: Use caution with beta-blockers; monitor for atrial fibrillation 1
• Thyroid storm: Medical emergency requiring hospitalization, aggressive treatment with PTU, beta-blockers, corticosteroids, and supportive care 8

Remember that untreated hyperthyroidism is associated with increased mortality, cardiac arrhythmias, heart failure, osteoporosis, and adverse pregnancy outcomes 7. Prompt diagnosis and appropriate treatment are essential to prevent these complications.