Hyperthyroidism

Propylthiouracil is a thiourea-derivative antithyroid agent. Propylthiouracil inhibits the synthesis of thyroid hormones by interfering with the incorporation of iodine into tyrosyl residues of thyroglobulin; the drug also inhibits the coupling of these iodotyrosyl residues to form iodothyronine.

Clinical improvement of hyperthyroidism begins within 24 to 36 h and remissions occur in 4 months; the duration of effect from a single 100-mg dose was 2 to 3 h ; elimination half-life ranges from 1.6 to 25 h.

hypersensitive to the drug

D

Propylthiouracil is distributed into milk to a small extent and, therefore, is unlikely to result in clinically important doses in the nursing infant. Some clinicians consider propylthiouracil to be a second-line agent in nursing women because of concerns regarding severe hepatotoxicity (i.e., hepatic necrosis in either woman or child) following maternal use of the drug; these clinicians state that methimazole is the preferred antithyroid drug in nursing women.

Adverse effects include agranulocytosis, leukopenia, hemolytic anemia, aplastic anemia, leukemia, disseminated intravascular coagulation, galactorrhea, porphyria, sexual dysfunction, hepatotoxicity, interstitial pneumonitis, rheumatoid arthritis, systemic lupus erythematosus, serum sickness, and ototoxicity.

Initial 50-100mg TID, maintenance 100-150mg TID.