title: Quinidine does not alter antipyrine metabolism.
abstract: Quinidine has been reported to be a potent inhibitor of a specific isozyme of cytochrome P-450 (P-450db 1) that is responsible for the metabolism of a select group of drugs. In order to investigate the potential for quinidine to inhibit other isozymes of cytochrome P-450 and to assess whether or not P-450db 1 plays any role in antipyrine metabolism, we studied the effects of quinidine pretreatment on the pharmacokinetics and metabolism of antipyrine in six healthy, male volunteers. Using a randomized, crossover study design with a 2-week washout period between treatments, subjects received a single 1 gram antipyrine dose alone or with quinidine sulfate 200 mg orally every 8 hours for 24 hours prior to the dose of antipyrine and over the 48 hours following antipyrine administration. Mean serum concentrations, apparent oral clearance (1.93 +/- 0.86 vs 2.06 +/- 1.06 L/hr with quinidine) and half-life (13.5 +/- 3.3 vs 12.4 +/- 3.6 hr with quinidine) were not significantly different between the two treatments. The fraction of the administered dose recovered as antipyrine and measured metabolites (56.7% vs 59% with quinidine) as well as the recovery of each individual metabolite was not altered with quinidine pretreatment. In addition, the mean formation clearances for norantipyrine, 4-hydroxyantipyrine and 3-hydroxymethylantipyrine exhibited no change between treatment phases.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: College of Pharmacy and Allied Health Professions, Wayne State University, Detroit, MI 48202.
authors.forename: S K
authors.initials: SK
authors.lastname: Bowles
authors.forename: L
authors.initials: L
authors.lastname: Cardozo
authors.forename: D J
authors.initials: DJ
authors.lastname: Edwards
mesh_terms: D000328:Adult; D000983:Antipyrine / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D001711:Biotransformation; D006207:Half-Life; D006801:Humans; D008297:Male; D011802:Quinidine / Q000494:pharmacology*; D011897:Random Allocation
chemical_list: D011802:Quinidine; D000983:Antipyrine