Thyroid drugs: thyroid storm: practice question

Try it

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Propylthiouracil first, then iodide at least an hour later, with propranolol and hydrocortisone

In thyroid storm, a thionamide (propylthiouracil is preferred since it also blocks T4 to T3 conversion) is given first to stop new hormone synthesis. Iodide is started at least an hour later to block hormone release; if given before the block it can supply substrate for more hormone. Propranolol controls adrenergic symptoms and steroids reduce conversion and support the adrenal axis.

Option by option

• A. Propylthiouracil first, then iodide at least an hour later, with propranolol and hydrocortisone (correct)

  Correct. Block synthesis first, then iodide to prevent release, with beta-blocker and steroid.

• B. Radioactive iodine immediately, then propranolol

  Radioactive iodine causes a release of stored hormone and takes weeks to act, so it worsens storm.

• C. Hydrocortisone alone, deferring antithyroid drugs until stable

  Steroids alone do not block synthesis or release, so the thyrotoxicosis continues.

• D. Potassium iodide first, with a thionamide started the next day

  Iodide before a thionamide can fuel further hormone synthesis.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Pharmacology questions