Ketamine dependence.

Ketamine hydrochloride is a safe and rapid-acting non-opioid, lipid soluble anaesthetic with a short elimination half-life that is used for medical and veterinary purposes. It produces a state of "dissociative anaesthesia", probably from action on N-methyl-D-aspartate (NMDA) receptors. The psychotropic effects of ketamine range from dissociation and depersonalization to psychotic experiences and include a sensation of feeling light, body distortion, absence of time sense, novel experiences of cosmic oneness and out-of-body experiences. Abuse of ketamine has been reported, the typical abuser being an individual who uses multiple drugs and has some contact with medical agencies. This case demonstrates the effects of large doses of ketamine in a person with polysubstance abuse. The case also highlights development of significant tolerance to ketamine without prominent withdrawal symptoms. Caution in use of ketamine is reiterated in light of its abuse liability.