title: Formation of a thiomethyl metabolite of phenacetin and acetaminophen in dogs and man.
abstract: Conjugates of 3-methylthio-4-hydroxyactanilide were found in the urine of dogs and humans treated with phenacetin (4-ethoxyacetanilide) or acetaminophen (4-hydroxyacetanilide). About 1% to 3% of the administered dose was excreted as this thiomethyl metabolite after administration of phenacetin or acetaminophen to dogs. An average of 0.39% of the dose was excreted in the urine as 3-methylthio-4-hydroxyacetanilide conjugates after administration of phenacetin to several subjects, and an average of 0.66% of the dose was excreted as this metabolite in the urine after administration of acetaminophen to humans. The possibility that the thiomethyl metabolite is derived from a mercapturic acid conjugate or an N-hydroxy derivative of phenacetin or acetaminophen is discussed.
mesh_terms: D000082:Acetaminophen / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000652:urine; D000293:Adolescent; D000328:Adult; D000818:Animals; D001711:Biotransformation; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D004285:Dogs; D005260:Female; D006801:Humans; D006868:Hydrolysis; D008297:Male; D010615:Phenacetin / Q000378:metabolism*
chemical_list: D000082:Acetaminophen; C035718:3-thiomethylparacetamol; D010615:Phenacetin