What is the initial treatment for hyperthyroidism?

Initial Treatment for Hyperthyroidism

The initial treatment for hyperthyroidism is methimazole (MMI) as the antithyroid drug of choice, with beta-blockers (such as propranolol or atenolol) added for symptom control in symptomatic patients. 1, 2

Diagnosis Confirmation

• Confirm hyperthyroidism with:
  • Low TSH
  • Elevated free T4 and/or free T3
  • Determine etiology (Graves' disease, toxic multinodular goiter, toxic adenoma, thyroiditis)

First-Line Treatment Options

Antithyroid Medications

• Methimazole (MMI) is the preferred antithyroid drug 3, 4:

  • More effective than propylthiouracil (PTU) in single daily dosing
  • Longer half-life allowing once-daily dosing
  • Fewer severe side effects
  • Typical starting dose: 15-30 mg daily (based on severity)

• Propylthiouracil (PTU) is second-line 5:

  • Reserved for patients who cannot tolerate methimazole
  • Preferred during first trimester of pregnancy
  • Has higher risk of severe liver injury
  • Requires multiple daily doses (typically 50-150 mg three times daily)

Symptomatic Treatment

• Beta-blockers (propranolol or atenolol) 1:
  • Add for symptomatic relief (palpitations, tremor, anxiety)
  • Continue until thyroid hormone levels normalize
  • Typical dose: propranolol 20-40 mg 3-4 times daily or atenolol 25-50 mg once daily

Treatment Selection Based on Etiology

Graves' Disease

• Initial treatment with antithyroid drugs (preferably MMI) for 12-18 months 6
• Note: 50% recurrence rate after standard course
• Consider long-term treatment (5-10 years) for lower recurrence rate (15%)

Toxic Nodular Goiter

• Antithyroid drugs for initial control
• Definitive treatment usually with radioactive iodine or surgery 6

Thyroiditis

• Beta-blockers for symptomatic relief
• Antithyroid drugs not effective (self-limiting condition)
• Consider steroids in severe cases 6

Monitoring and Follow-up

• Check thyroid function tests (TSH, free T4, free T3) every 4-6 weeks until stable
• Monitor for side effects of antithyroid drugs:
  • Rash, fever, joint pain (common)
  • Agranulocytosis, liver injury (rare but serious)

Special Considerations

Pregnancy

• PTU preferred in first trimester due to lower risk of birth defects
• Switch to MMI after first trimester 5

Severe Hyperthyroidism/Thyroid Storm

• Requires hospitalization
• Higher doses of antithyroid drugs
• Addition of beta-blockers, iodine solutions, and possibly glucocorticoids

Treatment Pitfalls to Avoid

• Don't use PTU as first-line except in first trimester pregnancy or MMI allergy
• Don't forget to add beta-blockers for symptomatic relief
• Don't overlook monitoring for serious side effects of antithyroid drugs
• Don't continue antithyroid drugs indefinitely without considering definitive treatment options (radioactive iodine or surgery) in appropriate cases

Definitive Treatment Options (after initial control)

1. Continue antithyroid drugs (especially for Graves' disease)
2. Radioactive iodine ablation (most common definitive treatment in the US)
3. Surgical thyroidectomy

The choice between these options depends on patient factors, disease severity, and patient preference 2.