Phencyclidine (PCP)
Phencyclidine (PCP, 'angel dust') is the prototype arylcyclohexylamine dissociative, developed in the 1950s as a surgical anaesthetic before withdrawal due to severe emergence reactions. It is an NMDA receptor antagonist producing dissociation, analgesia and, at higher doses, marked agitation, psychosis and anaesthesia. Among this class it has one of the larger human data sets, drawn mostly from clinical anaesthesia trials and decades of emergency-department case reports.
01 Overview
PCP was introduced as Sernyl for human surgical anaesthesia but abandoned when patients experienced prolonged delirium, agitation and hallucinations on emergence. It later spread as a recreational drug, typically smoked, insufflated or taken orally, and became notable for unpredictable behavioural toxicity including violent agitation and analgesia-driven self-injury.
Effects are strongly dose-dependent: low doses give stimulation and dissociation, higher doses cause ataxia, nystagmus, dissociative anaesthesia and, in overdose, hyperthermia, rhabdomyolysis, seizures and coma. Compared with newer arylcyclohexylamines, PCP carries a comparatively higher risk of agitation and toxicity, and its long, variable half-life increases the danger of redosing.
02 Mechanism
Non-competitive antagonist at the NMDA glutamate receptor (open-channel blocker), with additional activity at dopamine transporters and sigma sites contributing to its stimulant and psychotomimetic profile.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Common | 3–8 mg | Insufflated | Faster onset, shorter duration than oral. |
| Common | 5–10 mg | Oral | Highly variable street purity; effects unpredictable. |
| Strong | 10–20 mg | Oral | Heavy dissociation, agitation and anaesthesia risk. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| DissociationDetachment from body and environment, depersonalisation and derealisation. | Observational | ||
| AnalgesiaMarked reduction in pain perception, which can mask injury. | Observational | ||
| Stimulation and euphoriaEnergising, disinhibiting effect at lower doses. | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Agitation and psychosisParanoia, aggression, violent agitation and dissociative psychosis, sometimes prolonged. | Severe | Common at higher doses | Observational | |
| Ataxia and loss of coordinationNystagmus, unsteady gait and impaired motor control, with fall and injury risk compounded by analgesia. | Moderate | Very common | Observational | |
| Hyperthermia and rhabdomyolysisOverdose can cause elevated temperature, muscle breakdown, seizures, renal injury and coma. | Life-threatening | In overdose | Observational |