Pharmacodynamics of propylthiouracil in normal and hyperthyroid subjects after a single oral dose.

Serum levels of propylthiouracil were measured in 8 normal persons and in 7 patients with hyperthyroidism after a single, 300 mg, oral dose of 6-n-propyl-2-thiouracil (PTU). The patients with hyperthyroidism were restudied after 3, 6, and 9 weeks of individualized treatment with PTU. The serum half-life of the drug in normal subjects was 1.65 h. In patients with hyperthyroidism the serum half-life was similar, and it did not change significantly as the euthyroid state was achieved.