In vivo effect of 5- and 8-methoxypsoralens and cimetidine on R,S-warfarin metabolism in rat.

Several forms of cytochrome P-450 (CYP) metabolize R,S-warfarin in a regio- and enantioselective manner, therefore R,S-warfarin can be recognized as a metabolic probe for a number of CYP isoforms. We have applied a warfarin model in vivo in order to estimate the inhibitory properties of 5- and 8-methoxypsoralens on the activity of rat CYP isoforms. The area under the serum concentration versus time curve (AUC) values from time zero to 5 h for R- and S-warfarin and their metabolites were calculated.