Initial Treatment for Hyperthyroidism
Beta-blockers (atenolol 25-50 mg daily or propranolol) should be started immediately for symptomatic relief in all patients with hyperthyroidism, regardless of severity, while definitive therapy is being arranged. 1
Immediate Symptomatic Management
- Start beta-blocker therapy first to control tachycardia, palpitations, tremor, and anxiety while awaiting diagnostic workup and definitive treatment 1
- Titrate atenolol or propranolol to achieve heart rate <90 bpm if blood pressure allows 1
- Beta-blockers provide rapid symptom relief within hours to days, addressing the cardiovascular manifestations that most impact quality of life 1
Definitive Treatment Selection Based on Etiology
For Graves' Disease (Most Common Cause - 70% of Cases)
Antithyroid drugs (methimazole preferred) are the initial definitive treatment, with starting dose of 10-30 mg daily as a single dose 2, 3, 4
- Methimazole is the first-line antithyroid drug due to fewer major side effects, once-daily dosing, lower cost, and better availability 2, 3
- Starting dose should not exceed 15-20 mg/day to minimize risk of dose-dependent agranulocytosis 2
- Propylthiouracil should be reserved only for: first trimester pregnancy, patients intolerant to methimazole, or thyroid storm 5, 2, 3
- Critical warning: Propylthiouracil can cause severe liver failure requiring transplantation or death 5
For Toxic Nodular Goiter
Radioactive iodine (131I) is the treatment of choice, not antithyroid drugs, as these nodules will not remit with medical therapy alone 6, 4
- Antithyroid drugs should be stopped at least one week prior to radioiodine administration to reduce treatment failure risk 2
- Beta-blockers continue for symptom control until definitive treatment takes effect 1
For Thyroiditis (Self-Limited Hyperthyroid Phase)
Supportive care with beta-blockers only - no antithyroid drugs needed as this represents passive hormone release, not overproduction 1
- Monitor thyroid function every 2-3 weeks to detect transition to hypothyroidism (the most common outcome) 1
- Hyperthyroid phase typically resolves within weeks 1
- High-dose corticosteroids are NOT routinely required 1
Treatment Algorithm by Severity
Grade 1 (Asymptomatic/Mild Symptoms)
- Continue evaluation and treatment planning 1
- Beta-blocker for symptomatic relief if needed 1
- Close monitoring of thyroid function 1
Grade 2 (Moderate Symptoms, Able to Perform ADL)
- Consider holding immune checkpoint inhibitors if applicable 1
- Beta-blocker therapy mandatory 1
- Hydration and supportive care 1
- Endocrine consultation recommended 1
Grade 3-4 (Severe/Life-Threatening)
- Hold all immune checkpoint inhibitors 1
- Mandatory endocrine consultation 1
- Beta-blocker therapy 1
- Hospitalization for severe cases 1
- Additional medical therapies may include steroids, SSKI, or thionamides (methimazole or propylthiouracil) 1
- Consider surgery in refractory cases 1
Critical Pitfalls to Avoid
- Never use propylthiouracil as first-line therapy except in first trimester pregnancy or methimazole intolerance due to severe hepatotoxicity risk 5, 2
- Do not start antithyroid drugs for thyroiditis - this is self-limited and requires only symptomatic management 1
- Do not use antithyroid drugs as definitive therapy for toxic nodular goiter - these patients need radioiodine or surgery 2, 6, 4
- Monitor for agranulocytosis (fever, sore throat) especially in first 3 months of thionamide therapy 5, 2
- Stop propylthiouracil immediately if any signs of liver injury develop (nausea, vomiting, right upper quadrant pain, jaundice, dark urine) 5
Special Populations
Pregnancy
- Propylthiouracil is preferred in first trimester only due to methimazole association with aplasia cutis and choanal/esophageal atresia 1, 3
- Switch to methimazole after first trimester if possible 1
- Radioactive iodine is absolutely contraindicated 1, 6