What are the treatment options for hyperthyroidism?

Treatment Options for Hyperthyroidism

Methimazole is the preferred first-line medication for most patients with hyperthyroidism due to its once-daily dosing, lower risk of severe hepatotoxicity, and superior efficacy compared to propylthiouracil. 1

Initial Assessment and Treatment

Medication Options

• Antithyroid medications:

  • Methimazole (first-line): 15-30 mg daily depending on severity
    • 15 mg daily for mild to moderate hyperthyroidism
    • 30 mg daily for severe hyperthyroidism (FT4 ≥7 ng/dL) 2
  • Propylthiouracil: Reserved for special situations:
    • First trimester of pregnancy
    • Patients intolerant to methimazole
    • Thyroid storm 3

• Beta-blockers for symptomatic relief:

  • Atenolol 25-50 mg daily or propranolol 40-80 mg every 6-8 hours
  • Target heart rate <90 bpm if blood pressure allows 1

Definitive Treatment Options

1. Antithyroid medications (typically 12-18 months course)
2. Radioactive iodine ablation (contraindicated in pregnancy) 4
3. Thyroidectomy (surgical removal of thyroid gland)

Treatment Algorithm Based on Etiology

Graves' Disease (70% of cases) 5

1. Start methimazole with beta-blockers for symptomatic relief
2. Monitor thyroid function every 2-3 weeks initially
3. Once stabilized, consider definitive treatment options:
   • Continue antithyroid drugs (recurrence rate ~50% after 12-18 months)
   • Long-term antithyroid treatment (5-10 years) has lower recurrence (15%)
   • Radioactive iodine ablation
   • Thyroidectomy

Toxic Nodular Goiter (16% of cases) 5

1. Usually treated with radioactive iodine or thyroidectomy
2. Antithyroid drugs can be used for preparation before definitive treatment

Thyroiditis (3% of cases) 5

1. Often self-limiting; symptomatic treatment with beta-blockers
2. Steroids only in severe cases
3. Monitor for transition to hypothyroidism

Monitoring and Dose Adjustment

• Check thyroid function tests every 2-3 weeks initially
• Monitor for medication side effects:
  • Complete blood count (risk of agranulocytosis)
  • Liver function tests (risk of hepatotoxicity) 1
• Once clinically improved, gradually taper antithyroid medication doses

Special Considerations

Pregnancy

• Propylthiouracil preferred in first trimester due to lower risk of birth defects
• Consider switching to methimazole in second and third trimesters due to lower risk of maternal hepatotoxicity 3
• Use lowest effective dose to prevent fetal hypothyroidism

Severe Hyperthyroidism/Thyroid Storm

• Hospitalization recommended
• Combination therapy with:
  • Higher dose antithyroid drugs
  • Beta-blockers
  • Iodine solution (after antithyroid drugs started)
  • Corticosteroids in severe cases 1

Medication Cautions

• Methimazole: Rash, arthralgia, rare agranulocytosis
• Propylthiouracil: Higher risk of severe hepatotoxicity, ANCA-associated vasculitis
• Both drugs: Patients should report immediately any evidence of illness, particularly sore throat, skin eruptions, fever, headache, or general malaise 3

Long-term Follow-up

• After discontinuation of antithyroid drugs, monitor for:
  • Recurrence of hyperthyroidism (more common in younger patients, high initial T4, large goiter)
  • Development of hypothyroidism
• Lifelong monitoring recommended due to risk of thyroid dysfunction

The treatment approach should be tailored based on disease severity, patient age, comorbidities, and pregnancy status, with methimazole being the cornerstone of pharmacological management for most patients with hyperthyroidism.