TABLE 1

Recommended initial approach to thyrotoxicosis

Management areaRecommended plan
Diagnostic testsThyroid-stimulating hormone, free thyroxine (T4), free or total triiodothyronine (T3), thyroid-stimulating immunoglobulins, radioactive iodine uptake and scan
Symptomatic treatment of all patients (will not affect diagnostic tests)Propranolol 10–40 mg 3 or 4 times daily or
Atenolol 25–100 mg 1 or 2 times daily or
Metoprolol tartrate 25–50 mg 2 or 3 times daily
Thyroid-directed treatment—if any 1 of elevated thyroid-stimulating immunoglobulins or high uptake of iodine 123 or high uptake of technetium 99m pertechnetate (will affect diagnostic tests) is foundMethimazole dosing based on free T4 levels:

  • 1–1.5 × upper limit: 5–10 mg daily

  • 1.5–2 × upper limit: 10–20 mg daily

  • 2–3 × upper limit: 10–20 mg twice daily

  • Based on information from references 1,4,6.