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August 19, 1950


Author Affiliations


From the Department of Medicine, Harper Hospital and Wayne University College of Medicine.

JAMA. 1950;143(16):1407-1408. doi:10.1001/jama.1950.02910510025006

We have used a new antithyroid drug, 1-methyl-2-mercaptoimidazole (tapazol), in the treatment of 18 patients with hyperthyroidism during a six month period and have found it fully as efficient as thiouracil and propylthiouracil in this condition. Toxic reactions were not observed.

The new compound is one of the imidazoles and differs from the well known antithyroid drugs in that it has a five-membered rather than a six-membered ring. (See the accompanying structural formulas.)

Its powerful antithyroid activity was noted by Stanley and Astwood1 when they were testing a number of similar compounds by the radioactive iodine technic.2 A pronounced effect on iodine accumulation in the thyroid was noted with as little as 0.5 mg. of the compound, and 5.0 mg. completely inhibited the uptake of iodine for nearly twenty-four hours.

Comparative studies place the action of the drug above that of thiouracil, methylthiouracil, propylthiouracil and 2-mercaptoimidazole and rate