Effect of phencyclidine on hepatic drug metabolism in the rat

Phencyclidine, an anesthetic used in experimental animals, was examined for its effect on hepatic drug metabolism. Treatment of male rats for 4 days with phencyclidine (50 mg/kg/day, ip) caused significant increases in the rate of metabolism of hexobarbital, aminopyrine, and zoxazolamine in vitro by the 10,000 g hepatic supernatant fraction. Metabolism of p-nitroanisole in vitro was not altered by the drug treatment. Significant shortening of hexobarbital sleeping time was observed after phencyclidine treatment. Zoxazolamine paralysis time was increased by the drug treatment. The discrepancy between the zoxazolamine studies in vivo and in vitro appear to be due to alteration of the sensitivity of the rat to the paralyzing action of zoxazolamine since plasma concentrations at the time of recovery from zoxazolamine paralysis were lower in the treated animals.