Potassium perchlorate

General information

Potassium perchlorate is a thyrostatic drug that is still used (in a dose of 1000 mg/day or more) as an alternative to the thionamides, especially in cases of allergy and sometimes in cases of amiodarone-induced hyperthyroidism [ ]. It has also been used to treat the iodine-induced form of thyrotoxicosis, such as type 1 hyperthyroidism due to amiodarone (qv).

Compared with the thionamides, potassium perchlorate has two disadvantages:

• 1.

  treatment cannot be directly changed to radioiodine therapy, since perchlorate elimination lasts for some weeks;

• 2.

  brief high-dose iodine therapy cannot be used as a preoperative thyrostatic measure.

Potassium perchlorate produces goiter, as do the thionamides, but its effects on the hematological system are the main reason for using it sparingly.

The effects of potassium perchlorate on thyroid function have been retrospectively studied in 10 patients with amiodarone-induced thyrotoxicosis without underlying thyroid disease while they continued to take amiodarone [ ]. Potassium perchlorate restored euthyroidism in all patients within 28 (range 15–45) days, but after it was withdrawn all the patients became thyrotoxic again after 45 (range 30–60) days. One patient developed a mild leukopenia and one had a slight increase in serum creatinine, which normalized after withdrawal of potassium perchlorate. The authors recommended that potassium perchlorate should not be used as a first-line treatment for thyrotoxicosis if amiodarone needs to be continued.