Phencyclidine ingestion: drug abuse and psychosis.

Phencyclidine (PCP) is a popular illicit drug often misrepresented as some other hallucinogenic substance and distributed in widely varying dosage forms and strengths. Users of hallucinogenic drugs may present with unintentional PCP overdoses. Toxicological laboratory analyses are essential to establish the diagnosis. In nine admitted overdose patients, the consciousness level ranged from alert to comatose on presentation, and all showed a prolonged recovery phase with agitation and toxic psychosis. Severe behavior disorder, paranoid ideation, and amnesia for the entire period of in-hospital stay are characteristic. In very high dose patients, shallow respiratory excursions and periods of apnoea and cyanosis coincided with generalized extensor spasm and spasm of neck muscles. Excessive bronchial secretions, gross ataxia, opisthotonic posturing, and grimacing occur. PCP toxic psychosis should be considered in drug-abusing patients presenting with schizophrenic-like symptoms, psychosis, or other bizarre behavior, whether or not they admit to taking PCP.