title: Enhanced phenacetin metabolism in human subjects fed charcoal-broiled beef.
abstract: There were marked individual differences in the plasma levels of phenacetin after oral administration of a 900-mg dose to 9 normal volunteers eating customary home diet. Feeding a diet that contained charcoal-broiled beef for 4 days prior to the administration of phenacetin markedly decreased the plasma levels of this drug without appreciably influencing the plasma concentrations of phenacetin's metabolite, N-acetyl-p-aminophenol (APAP), or the plasma half-life of phenacetin. The average peak concentration of phenacetin in plasma, after a 900-mg oral dose, fell from 1,628 ng/ml, when the subjects were fed a control diet for 7 days, to 352 ng/ml after they were fed the same diet which contained charcoal-broiled beef for 4 days. The average peak concentration of phenacetin rose to 1,885 ng/ml after the subjects were subsequently fed the control diet for 7 days. The ratios of the average concentrations of APAP in plasma to those of phenacetin markedly increased after the charcoal-broiled beef diet. The results suggest that a diet containing charcoal-broiled beef enhances the metabolism of phenacetin in the gastrointestinal tract and/or during its first pass through the liver. This effect greatly decreases the bioavailability of phenacetin.
mesh_terms: D000082:Acetaminophen / Q000097:blood; D000328:Adult; D002606:Charcoal / Q000494:pharmacology*; D003296:Cooking; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D008460:Meat; D010615:Phenacetin / Q000097:blood / Q000378:metabolism*; D013997:Time Factors
chemical_list: D002606:Charcoal; D000082:Acetaminophen; D010615:Phenacetin