Which medication is used to treat a thyroid storm?

The treatment of a thyroid storm—an acute, life-threatening exacerbation of hyperthyroidism—primarily involves the use of antithyroid medications to rapidly decrease thyroid hormone production. Propylthiouracil (PTU) is effective for this purpose because it inhibits both the synthesis of thyroid hormones and the peripheral conversion of T4 to the more active T3. This dual action makes it particularly useful in managing the excessive hormone levels seen during a thyroid storm.

Levothyroxine is not appropriate for treating a thyroid storm, as it is a synthetic form of thyroxine used to treat hypothyroidism, not hyperthyroidism. Carbimazole and methimazole are also antithyroid medications that can be used to manage hyperthyroidism, but they may not be as effective in the acute setting of a thyroid storm as PTU, especially because PTU acts quickly in inhibiting the peripheral conversion of hormones. Thus, propylthiouracil is preferred in the urgent management of a thyroid storm.