Pharmacology of propylthiouracil in thyrotoxicosis and chronic renal failure.

The simultaneous occurrence of thyrotoxicosis and renal failure has rarely been reported in the literature, and data concerning appropriate antithyroid drug management in this circumstance are limited. We studied propylthiouracil pharmacokinetics in one such patient basally and while the patient was receiving hemodialysis. On a day when the patient was not receiving hemodialysis, propylthiouracil serum levels were high, but serum propylthiouracil half-life was not prolonged. During hemodialysis, serum propylthiouracil levels were normal, and the time to peak serum levels was delayed; the disappearance of the drug from the serum was normal after hemodialysis was completed. The amount of propylthiouracil that appeared in the dialysate was approximately 5% of the administered dose. These data suggest that propylthiouracil can be administered in standard dosages to patients with thyrotoxicosis and renal failure.