Treatment	Mechanism of action	Indications	Contraindications and complications
Beta blockers	Inhibit adrenergic effects	Prompt control of symptoms; treatment of choice for thyroiditis; first-line therapy before surgery, radioactive iodine, and antithyroid drugs; short-term therapy in pregnancy	Use with caution in older patients and in patients with pre-existing heart disease, chronic obstructive pulmonary disease, or asthma
Iodides	Block the conversion of T4 to T3 and inhibit hormone release	Rapid decrease in thyroid hormone levels; preoperatively when other medications are ineffective or contraindicated; during pregnancy when antithyroid drugs are not tolerated; with antithyroid drugs to treat amiodarone- (Cordarone-) induced hyperthyroidism	Paradoxical increases in hormone release with prolonged use; common side effects of sialadenitis, conjunctivitis, or acneform rash; interferes with the response to radioactive iodine; prolongs the time to achieve euthyroidism with antithyroid drugs
Antithyroid drugs (methimazole [Tapazole] and PTU)	Interferes with the organification of iodine; PTU can block peripheral conversion of T4 toT3 in large doses	Long-term treatment of Graves’ disease (preferred first-line treatment in Europe, Japan, and Australia); PTU is treatment of choice in patients who are pregnant and those with severe Graves’ disease; preferred treatment by many endocrinologists for children and for adults who refuse radioactive iodine; pretreatment of older and cardiac patients before radioactive iodine or surgery; both medications considered safe for use while breastfeeding	High relapse rate; relapse more likely in smokers, patients with large goiters, and patients with positive thyroid-stimulating antibody levels at end of therapy; major side effects include polyarthritis (1 to 2 percent), agranulocytosis (0.1 to 0.5 percent); PTU can cause elevated liver enzymes (30 percent), and immunoallergic hepatitis (0.1 to 0.2 percent); methimazole can cause rare cholestasis and rare congenital abnormalities; minor side effects (less than 5 percent) include rash, fever, gastrointestinal effects, and arthralgia
Radioactive iodine	Concentrates in the thyroid gland and destroys thyroid tissue	High cure rates with singledose treatment (80 percent); treatment of choice for Graves’ disease in the United States, multinodular goiter, toxic nodules in patients older than 40 years, and relapses from antithyroid drugs	Delayed control of symptoms; posttreatment hypothyroidism in majority of patients with Graves’ disease regardless of dosage (82 percent after 25 years); contraindicated in patients who are pregnant or breastfeeding; can cause transient neck soreness, flushing, and decreased taste; radiation thyroiditis in 1 percent of patients; may exacerbate Graves’ ophthalmopathy; may require pretreatment with antithyroid drugs in older or cardiac patients
Surgery (subtotal thyroidectomy)	Reduces thyroid mass	Treatment of choice for patients who are pregnant and children who have had major adverse reactions to antithyroid drugs, toxic nodules in patients younger than 40 years, and large goiters with compressive symptoms; can be used for patients who are noncompliant, refuse radioactive iodine, or fail antithyroid drugs, and in patients with severe disease who could not tolerate recurrence; may be done for cosmetic reasons	Risk of hypothyroidism (25 percent) or hyperthyroid relapse (8 percent); temporary or permanent hypoparathyroidism orlaryngeal paralysis (less than 1 percent); higher morbidity and cost than radioactive iodine; requires patient to be euthyroid preoperatively with antithyroid drugs or iodides to avoid thyrotoxic crisis