Treatment of Hyperthyroidism in Graves Disease
This protocol applies to hyperthyroidism arising specifically from Graves disease, where autoimmune mechanisms drive excess thyroid hormone production.
Clinical Scenario
Graves disease is the most common cause of hyperthyroidism in the United States. It is an autoimmune disorder in which thyroid-stimulating antibodies activate TSH receptors, triggering thyroid hormone synthesis.
Treatment Approach
Initial management involves antithyroid medication from the thionamide class; the specific agent chosen depends on individual patient factors — the full selection criteria and regimen are in the protocol.
Treatment Goals
The target is normalization of thyroid function, with free T4 and total T3 levels returning to normal, reassessed at follow-up after starting therapy.
References
- Graves disease, the most common cause of hyperthyroidism in the United States, is an autoimmune disorder in which thyroid-stimulating antibodies activate thyroid-stimulating hormone (TSH) receptors, triggering thyroid hormone synthesis.
- Graves disease requires one of the three treatment options: an antithyroid medication (methimazole [Tapazole] or propylthiouracil), radioactive iodine (I-131) ablation of the thyroid gland, or surgical thyroidectomy.
- Because Graves disease remits in up to 30% of patients treated with thionamides, these medications can be used as the initial treatment, with ablation or thyroidectomy performed if remission does not occur.
- Because use of propylthiouracil has a higher risk of causing severe liver injury, as highlighted in the U.S. Food and Drug Administration's boxed warning, methimazole is preferred except during the first trimester of pregnancy (can cause birth defects) and in patients with an adverse reaction to methimazole.
- An antithyroid medication should be continued for 12 to 18 months, then tapered or discontinued if the TSH level is normal at the time.
- Free T4 and total T3 should be obtained four weeks after starting a thionamide and every four to eight weeks thereafter with the dosage adjusted based on results.
- Once free T4 and total T3 levels normalize, they should be monitored every three months.