THIOURACILS AND THIOUREAS

IN THE ATTEMPT to obtain antithyroid compounds which were superior to 2-thiouracil, it seemed important not only to test the thyroid-inhibiting effects of many related substances in animals 1 but also to compare the activities of the more potent goitrogenic compounds in patients with thyrotoxicosis. 2 Moreover, it was regarded as important to investigate the differences in the manner in which the body handles these drugs, especially as regards their absorption, distribution, destruction and excretion. Studies of this nature have previously been made with thiouracil, 3 thiourea, 4 diethylthiourea, 2c tetramethylthiourea 2c and aminothiazole. 2g All these drugs are rapidly absorbed from the gastrointestinal tract and destroyed in the body. None of the first four compounds is excreted in the stools; approximately one third of these substances is excreted in the urine. In the case of thiouracil, which has been studied more extensively than the other compounds, the following significant observations have been