ORAL KETAMINE PRODUCES A DOSE-DEPENDENT CNS DEPRESSION IN THE RAT

The oral to parenteral potency of ketamine to produce central nervous system (CNS) depression was estimated in rats using a behavioral scale . As a function of dose, ketamine produces CNS depression that ranges from ataxia to anesthesia by either route of administration. The oral ED(50) value for ketamine was 120 mg/kg (82.2-159.2, 95% CI) while the intravenous ED(50) value was 3.7 mg/kg (2.4-5.1, 95% CI). Oral ketami ne produces CNS effects comparable to intravenous ketamine, although t he drug is approximately 32 fold less potent by the oral route.