[Serum level and urinary excretion of 14C-thiamozol in patients with hyperthyroidism (author's transl)]

2-(14C) Thiamazol (Favistan) was administered intravenously in a therapeutically subthreshold dose to seven control subjects and five patients with hyperthyroidism. In both groups the reduction of plasma radioactivity occurred with at least two exponentials. Half-life was calculated to be 35 minutes for the faster and 28 hours for the slower process in the control group, and 12 minutes and about 20 hours, respectively, in the hyperthyroid patients. Forty-eight hour urinary excretion of the injected radioactive material was about 80% for the hyperthyroid patients and 87% for the control subjects. Maximal activity in urine occurred about six hours after injection. There was practically no demonstrable plasma-protein binding of the drug in in-vitro experiments. As the pharmacokinetics of the drug are not influenced in thyroid disease, there is apparently no need to adapt thyrostatic dosage in hyperthyroid states.