Overview & substances

PCP is a dissociative hallucinogen originally developed as an anesthetic. Related substances include ketamine and some synthetic designer dissociatives. Use ranges from episodic recreational use to problematic patterns causing persistent psychiatric morbidity.

Typical clinical features

• Acute: nystagmus (vertical or horizontal), dissociation, hallucinations, delusions, severe agitation, combativeness, analgesia, and unpredictably altered sensorium.
• Autonomic: hypertension, tachycardia, hyperthermia and diaphoresis.
• Neurological: seizures (less common), ataxia, and confusion; persistent psychosis can occur in some users.

Recognition & assessment

1. Scene safety: patients may be violent — ensure staff safety and consider police/security if risk to others.
2. Rapid history: substance (PCP, ketamine, other dissociative), route, time since use, co‑ingestants (stimulants, alcohol), and past psychiatric history.
3. Examination: mental state, pupils, nystagmus, vitals, temperature and possible trauma from aggressive behaviour.
4. Investigations: ECG, electrolytes, blood glucose, tox screen (limited for PCP), imaging if head injury suspected, and creatine kinase if rhabdomyolysis suspected.

Immediate management — de‑escalation & medical care

• Prioritise safety: low‑stimulus environment, minimal staff, calm voice and clear instructions; avoid physical confrontation where possible.
• Benzodiazepines are first‑line for severe agitation and psychomotor excitation (e.g., lorazepam 2–4 mg IV/IM incremental dosing) — repeat to effect and monitor respiratory status.
• Antipsychotics (e.g., haloperidol) can be used for severe psychosis or agitation not controlled with benzodiazepines, but use cautiously due to potential for lowering seizure threshold and interaction with hyperthermia/catecholamine surge.
• Rapid control may require ketamine/other sedatives in controlled settings, but these are specialist interventions; consider physical sedation only when medically necessary and with monitoring.
• Address hyperthermia vigorously (cooling, IV fluids) and check for rhabdomyolysis — measure CK and renal function.

Complications to monitor

• Trauma and injuries from aggression or falls — perform trauma screen and imaging as indicated.
• Rhabdomyolysis from prolonged agitation — check CK, urine output and renal function; treat with aggressive IV fluids and consider ICU if severe.
• Hyperthermia and autonomic instability — manage in ED/ICU as required.
• Persistent psychosis — consider psychiatric admission and antipsychotic treatment if symptoms continue after intoxication period.

Psychiatric management & follow‑up

• Many acute symptoms resolve with time and supportive care, but persistent psychosis or mood disturbance requires psychiatric evaluation and often antipsychotic therapy.
• Brief psychosocial interventions, motivational interviewing and referral to addiction services support engagement; there is limited evidence for pharmacological relapse prevention.
• Cognitive and functional assessments may be useful for recurrent users, with referral to community rehab and psychosocial supports.

Harm reduction & patient advice

• Advise avoidance of further use, especially in combination with stimulants or alcohol which increase medical risks.
• Encourage using with trusted companions, having plans to seek help if agitation or severe reactions occur, and avoiding driving or operating machinery after use.
• Provide education on signs that require urgent care: severe agitation, loss of consciousness, high fever, seizures, chest pain or difficulty breathing.

Key takeaways

• PCP intoxication can be unpredictable with severe agitation, violence, autonomic instability and medical complications — prioritise safety and medical stabilization.
• Benzodiazepines are first‑line for agitation; antipsychotics reserved for refractory psychosis with monitoring.
• Monitor for hyperthermia, rhabdomyolysis and trauma; arrange psychiatric follow‑up for persistent symptoms and addiction referral for recurrent use.