The perchlorates block the enzyme NIS, inhibiting iodine accumulation in the thyroid and favour the elimination of intrathyroidal iodine unused for hormone synthesis. Their therapeutical utilisation actually is limited due to the toxicity. In the literature there are different opinions regarding the adverse effects (nephrotic syndrome, irreversible aplastic anemia etc.), but several authors sustain that these appear only after high doses, and after the development of therapeutical actions.
Perchlorates are used rarely in the treatment of hyperthyroidism, mainly in iodine-, especially amiodarone-induced forms. They are indicated also to prevent these forms, using perchlorates pre- and postinterventionally with iodine-containing substances (e.g.contrast agents). In hyper-thyroidism induced by amiodarone, perchlorates are usually associated with thioamides. Similarly, these drugs can be attempted in cases of intolerance to other antithyroid drugs, e.g. thioamides, when can not be applied ablative measures.
We report two cases of hyperthyroidism treated with perchlorates, obtaining good therapeutical results. In both cases perchlorates were introduced after (hema-to-lo-gic and CNS) adverse effects produced by methimazole, alone and associated with lithium carbonate. Taking into account the recommended short duration of the therapy with perchlorates (not excee-ding 1 month) and lacking the possibilities for other efficient and durable conservative treatment (both pa-tients presented Hashitoxicosis aggravated through iodine intake, and had thioamide-intolerance), we indicated thyroidectomy after obtaining euthyroidism with perchlorates. At 710 days after surgery their thyroid status evolu-a-ted to hypothyroidism, so now they are receiving thyroxine substitution under longitudinal follow-up.