Administration of equally divided doses of propylthiouracil every two-eight hours in hyperthyroidism.

Serum propylthiouracil semi splitting occurs in 1.1 and 1.65 hours when administered in a single dose. In this work treatment for hyperthyroid patients is described; 350 mg were administered daily in divided doses, every two and eight hours. In group A fifteen patients received 50 mg every two hours from 8:00 to 20:00 hs. and in group B nine patients were administered 100, 100 and 150 mg at 8 hour intervals. The patients were hospitalized the first seven days and during this time circulating triiodothyronine and thyroxine concentrations were measured daily at 8:00 and 20:00 hrs. and then at 8:00 hrs. at days 8, 14, 21 and 28. After almost one week of treatment, in group "A", seven patients (46.6 per cent p 0.05) had normal concentration levels in both hormones. In group "B" only one patient reached normal levels in the first eight days. The administration of propylthiouracil every two hours is a useful procedure to attain the euthyroid state in less time than with other therapeutic patterns without undesirable side effects.