[Metabolic drug-drug interactions of chlorphenethiazine and chlorpromazine]

Owing to enzyme induction, the pretreatment of female Wistar rats with chlorphenethazine (Marophen, Elroquil) causes a shortening of the hexobarbital sleeping time and an increase in aminophenazone-N-, codeine phosphate-O- and p-nitroanisole-O-demethylation, a slight stimulation of p-nitrophenol-glucuronidation, but no change in aniline hydroxylation in the 9000-g-supernatant of liver homogenates. Comparative studies with chlorpromazine (Propaphenin) showed almost identical inductive activities which were in both cases inferior to that of phenobarbital. Consequently, the occurrence of drug-drug interactions of chlorphenethazine and chlorpromazine cannot be excluded in the framework of combined therapy.