RESUMEN
Thiouracil, 2-sulfanylidene-1H-pyrimidin-4-one, has been used as anti-thyroid, coronary vasodilator, and in congestive heart failure. It was found to cause agranulocytosis and it is suspected to be teratogenic and carcinogenic. Owing to its high frequency of adverse reactions, especially agranulocytosis, its use was abandoned in favor of other, less toxic drugs, such as propylthiouracil and methimazole. Thiouracil refers both to a specific molecule consisting of a sulfated uracil and a family of molecules based upon the structure. An important member of this family is propylthiouracil, which is a thiourea antithyroid drug that acts by blocking the production of thyroid hormones; it also inhibits the peripheral deiodination of thyroxine to tri-iodothyronine. This profile is prepared to discuss and explain physical and chemical properties, proprietary and nonproprietary names of thiouracil and propylthiouracil. It also includes uses and applications, methods of preparation, thermal and spectral behavior and methods of analysis. In addition, metabolism, excretion and pharmacology of propylthiouracil are also discussed.