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The Effects of Encainide versus Diltiazem on the Oxidative Metabolic Pathways of Antipyrine
Author(s) -
Bottorff Michael B.,
Lalonde Richard L.,
Kazierad David J.,
Hoon Timothy J.,
Tsiu Sandra J.,
Mirvis David M.
Publication year - 1989
Publication title -
pharmacotherapy: the journal of human pharmacology and drug therapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.227
H-Index - 109
eISSN - 1875-9114
pISSN - 0277-0008
DOI - 10.1002/j.1875-9114.1989.tb04143.x
Subject(s) - diltiazem , oxidative metabolism , pharmacokinetics , chemistry , metabolism , medicine , oral administration , metabolite , half life , endocrinology , elimination rate constant , pharmacology , oxidative phosphorylation , biochemistry , calcium , volume of distribution
The effects of diltiazem and encainide on the pharmacokinetics and metabolism of antipyrine were compared in nine healthy male volunteers. Diltiazem 90 mg every 8 hours for 5 days decreased the oral clearance of antipyrine from 2.34 to 1.86 L/hour (p < 0.05) and increased half‐life from 12.7 to 15.9 hours (p < 0.05). Diltiazem reduced the formation rate constants for 3‐hydroxymethylantipyrine by 27% (p < 0.05) and 4‐hydroxyantipyrine by 37% (p < 0.05). There was also a 21% reduction in the formation rate constant for norantipyrine (0.05 < p < 0.10). Encainide 25 mg every 8 hours for 5 days had no apparent effect on the oral clearance or half‐life of antipyrine, or on the formation rate constants for metabolites of antipyrine. In contrast to a previously published report in rats, encainide, unlike diltiazem, does not inhibit the oxidative metabolism of antipyrine in humans.