Anion Inhibitors

ANION INHIBITORS

Monovalent anions such as perchlorate (ClO₄^–), pertechnetate (TcO₄^–), and thiocyanate (SCN^–) can block uptake of iodide by the gland through competitive inhibition of the iodide transport mechanism. Since these effects can be overcome by large doses of iodides, their effectiveness is somewhat unpredictable.

The major clinical use for potassium perchlorate is to block thyroidal reuptake of I^– in patients with iodide-induced hyperthy-roidism (eg, amiodarone-induced hyperthyroidism). However, potassium perchlorate is rarely used clinically because it is associ-ated with aplastic anemia.