Gradual dose titration regime in thyrotoxicosis

Starting dose depends on the severity of the hyperthyroidism and the size of the thyroid gland

• thiamazole
  • in mild hyperthyroidism and small glands - 10–15 mg daily
  • severe hyperthyroidism and large thyroids need 20–40 mg daily
• carbimazole
  • equivalent dose is 140% of that of thiamazole.
• propylthiouracil
  • usually 50–150 mg administered three times daily.

Thyroid function is measured every 4-6 weeks after initiation of therapy and dose is progressively lowered at regular intervals to allow endogenous synthesis of thyroid hormone to continue in a regulated fashion (1,2).

Once euthyroidism is achieved:

• a maintenance dose of thiamazole of 5–10 mg daily, or 50 mg propylthiouracil two or three times daily, or lower
• thyroid function is measured every 2-3 months
• treatment shouldbe continued for 12-18 months (some suggest an even longer duration of therapy) (1)

Reference:

• (1) De Leo S, Lee SY, Braverman LE. Hyperthyroidism. Lancet (London, England). 2016;388(10047):906-918.
• (2) Vaidya B, Pearce SH. Diagnosis and management of thyrotoxicosis. BMJ. 2014;349:g5128