title: Evidence for a dual action of sulphinpyrazone on drug metabolism in man: theophylline-sulphinpyrazone interaction.
abstract: The effects of sulphinpyrazone administration on the metabolic and renal clearances of theophylline in man were investigated. Sulphinpyrazone increased total plasma theophylline clearance by 22%. This was the sum of increases in metabolic clearances by 3-demethylation (32%), 1-demethylation (30%) and 8-oxidation (22%) and of a decrease in renal clearance (27%). It is proposed that sulphinpyrazone has differential effects on at least two forms of cytochrome P-450 inhibiting one enzyme or group of enzymes which metabolises tolbutamide, phenytoin and S(-)warfarin and inducing a form (or forms) which metabolises theophylline, antipyrine and R(+)warfarin.
mesh_terms: D000328:Adult; D004347:Drug Interactions; D006801:Humans; D007700:Kinetics; D008297:Male; D013442:Sulfinpyrazone / Q000494:pharmacology*; D013806:Theophylline / Q000378:metabolism*
chemical_list: D013806:Theophylline; D013442:Sulfinpyrazone