A FOUR-YEAR STUDY OF THE TREATMENT OF HYPERTHYROIDISM WITH METHIMAZOLE*

Abstract

AS a result of Stanley and Astwood's (1) observations on the inhibitory effect of 1-methyl-2-mercaptoimidazole (methimazole) on the uptake of radioiodine by the human thyroid, early in 1949 we began to test the value of this and several closely allied imidazoles in patients with thyrotoxicosis. Using technics developed by Astwood and his associates (1–3), we simultaneously studied the relative intensities of the inhibitory effects of these compounds upon the uptake of radioiodine by the human thyroid (4). As a result of these early studies, it was decided to test the long-range usefulness of methimazole in the management of thyrotoxicosis. Since the earlier reports (1, 4–9), several articles have appeared regarding the effect of this drug in the treatment of hyperthyroidism (10–25). Although these represent studies with approximately 700 patients, most of the reports refer to short-term observations. Moreover, there is considerable divergence of opinion regarding the effectiveness and the toxicity of the compound. Conflicting claims that 1) it is too toxic for other than preoperative use (19), and 2) no untoward reactions have been seen (4, 5, 10), have appeared almost simultaneously. A summary of a long-term study seems, therefore, all the more timely.