1. n. 1-(1-phenylcyclohexyl)piperidine (phencyclidine): a hallucinogenic drug sometimes referred to as a “psychedelic anesthetic” because it was originally developed as an amnestic analgesic for use in surgical contexts and was later found to produce a psychedelic or dissociative reaction. Its medical use was discontinued because of adverse reactions, including agitation, delirium, disorientation, and hallucinations. High doses may induce stupor or coma. PCP has a complex mechanism of action. It binds as an antagonist to the NMDA receptor; it also acts as a dopamine-receptor agonist and blocks the reuptake of dopamine, norepinephrine, and serotonin, among other actions. Because intoxication with PCP can produce symptoms resembling both the positive and negative symptoms of schizophrenia, some consider it to be a useful drug model of that disorder. PCP became common as an illicit drug in the 1970s. It can be smoked (often in combination with marijuana or tobacco), insufflated (inhaled nasally), or taken orally or intravenously (see angel dust). Despite speculation about its potential to damage nerve tissue, PCP remains a popular illicit drug. It is still used in veterinary medicine, primarily as an immobilizing anesthetic during surgical procedures. See also hallucinogen.

2. abbreviation for primary care provider.