Effect of acute and chronic ethanol pre-treatment on the disposition of phencyclidine (PCP) in the rat

Disposition of [³H] Phencyclidine in brain, plasma and adipose tissue of rats acutely and chronically-treated with ethanol was studied using a method possessing high sensitivity and specificity for PCP. In rats acutely-treated with ethanol (5 g/kg PO dose) and PCP (10 mg/kg IP dose), dispositional factors did not play a role in the intensified pharmacological and behavioral effects of PCP. However in rats chronically-treated with 2.5 g/kg PO dose of ethanol twice a day for 19 days, the disposition of PCP (5 mg/kg IP dose) was significantly altered and the values of PCP in brain, plasma and adipose tissue were significantly higher than those in the control group. Although inhibition of PCP metabolism and a comparatively slower rate of its elimination appear to account for the potentiation of drug effects in animals chronically-treated with ethanol, interaction of drugs at the level of the central nervous system cannot be ruled out.