Drug Effects on Deiodinases

This episode examines how common medications alter thyroid hormone economy by targeting the iodothyronine deiodinase enzyme system. We contrast propylthiouracil, which selectively blocks type one deiodinase through a covalent mechanism, with amiodarone, which powerfully inhibits both type one and type two deiodinases to alter systemic feedback. Finally, we review the lipophilicity dependent effects of propranolol and the multi level impact of glucocorticoids, providing a rational framework for managing thyroid storm and interpreting complex laboratory profiles.