What are the treatment options for hyperthyroidism?

Treatment for Hyperthyroidism

Beta-blockers (propranolol or atenolol) should be initiated immediately for symptomatic relief, followed by antithyroid drugs (methimazole preferred over propylthiouracil except in first trimester pregnancy), with radioactive iodine or thyroidectomy reserved for definitive treatment in appropriate candidates. 1, 2

Initial Symptomatic Management

• Beta-blockers are the first-line symptomatic treatment for all patients with hyperthyroidism, particularly those with cardiac symptoms like tachycardia and tremor 1, 2
• Propranolol or atenolol should be started immediately while waiting for antithyroid medications to take effect, which typically takes several weeks 1, 2
• Beta-blockers can be continued until thioamide therapy reduces thyroid hormone levels to the therapeutic range 2

Antithyroid Drug Therapy

Drug Selection

• Methimazole is the preferred antithyroid drug for most patients due to superior efficacy, once-daily dosing, lower cost, and fewer major side effects 3, 4, 5
• Methimazole 15 mg once daily is significantly more effective than propylthiouracil 150 mg once daily in inducing euthyroidism, achieving therapeutic goals in 77% vs 19% of patients at 12 weeks 3
• Propylthiouracil is indicated only for specific situations: patients intolerant to methimazole, first trimester pregnancy (due to lower risk of congenital anomalies), and preparation for surgery/radioiodine when methimazole cannot be used 1, 2, 6

Treatment Duration and Monitoring

• Standard course is 12-18 months for Graves' disease, though long-term treatment (5-10 years) reduces recurrence rates from 50% to 15% 5
• Monitor thyroid function every 2-4 weeks initially, then every 4-6 weeks once stable 2
• Critical safety monitoring: Watch for agranulocytosis (fever, chills, sore throat), hepatitis (jaundice, dark urine, right upper quadrant pain), vasculitis, and thrombocytopenia—these require immediate drug discontinuation 1, 2, 6

Pregnancy-Specific Considerations

• Propylthiouracil is preferred in the first trimester due to association of methimazole with aplasia cutis and choanal/esophageal atresia 2, 7
• Methimazole can be used after the first trimester 1
• Goal is maintaining FT4 in the high-normal range using the lowest possible thioamide dosage 2
• Both drugs are safe during breastfeeding 2, 7
• Radioactive iodine is absolutely contraindicated during pregnancy and lactation 1, 2

Definitive Treatment Options

Radioactive Iodine (131I)

• Radioactive iodine is the treatment of choice for toxic nodular goiter and increasingly used as first-line therapy for Graves' disease 8, 5
• Well tolerated with the primary long-term consequence being hypothyroidism requiring lifelong thyroid hormone replacement 2, 8
• Pregnancy must be avoided for 4 months following administration 8
• May worsen Graves' ophthalmopathy; corticosteroid cover can reduce this risk 8

Thyroidectomy

• Indications for surgery include: large goiters causing compressive symptoms, suspicious nodules, severe ophthalmopathy, failed medical therapy, or patient intolerance to antithyroid drugs 1, 2, 8
• Near-total or total thyroidectomy is recommended when surgery is chosen 2
• Requires lifelong thyroid hormone replacement post-operatively 2
• Reserved for pregnant women who do not respond to thioamide therapy 1, 2

Severity-Based Management Algorithm

Mild (Grade 1): Asymptomatic or Mild Symptoms

• Continue treatment with beta-blockers for symptomatic relief 9, 1
• Initiate antithyroid drugs (methimazole preferred) 1, 2
• Monitor thyroid function every 2-3 weeks to catch transition to hypothyroidism 9

Moderate (Grade 2): Moderate Symptoms, Able to Perform ADL

• Consider holding immune checkpoint inhibitors if applicable until symptoms return to baseline 9
• Endocrine consultation recommended 9, 1
• Beta-blockers, hydration, and supportive care 9, 1
• For persistent thyrotoxicosis beyond 6 weeks, refer to endocrinology for additional workup 9

Severe (Grade 3-4): Life-Threatening or Unable to Perform ADL

• Mandatory hospitalization and endocrine consultation 9, 1
• Hold immune checkpoint inhibitors until symptoms resolve 9, 1
• Aggressive management with beta-blockers, high-dose antithyroid drugs, hydration, and supportive care 1, 2
• Consider additional therapies including steroids, SSKI (saturated solution of potassium iodide), or possible surgery 9

Special Clinical Scenarios

Thyroiditis-Induced Hyperthyroidism

• Thyroiditis is self-limited and typically resolves in weeks with supportive care alone 9, 2
• Treatment focuses on symptom management with beta-blockers rather than antithyroid drugs 2
• Most patients transition to primary hypothyroidism, requiring close monitoring and eventual thyroid hormone replacement 9, 2

Toxic Nodular Goiter

• Antithyroid drugs will not cure toxic nodular goiter—they only provide temporary control 8
• Radioactive iodine is the treatment of choice for definitive management 8, 5
• Surgery is an alternative for patients who refuse or cannot receive radioiodine 8

Common Pitfalls to Avoid

• Never use propylthiouracil as first-line except in first trimester pregnancy or methimazole intolerance—it carries higher risk of severe hepatotoxicity including liver failure and death 6
• Do not delay beta-blocker initiation while waiting for antithyroid drug effects 1, 2
• Avoid radioactive iodine in patients with active moderate-to-severe Graves' ophthalmopathy without corticosteroid prophylaxis 8
• Do not assume all hyperthyroidism requires long-term antithyroid drugs—thyroiditis requires only supportive care 9, 2