Phencyclidine Toxicity Clinical Presentation

Updated: Mar 28, 2022
  • Author: Patrick L West, MD; Chief Editor: Michael A Miller, MD  more...
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Because of the numerous routes of administration, variations in dosage, and possibility of co-ingestants, phencyclidine (PCP) produces a wide variety of physical and behavioral effects. Most commonly, witnesses may report agitation, bizarre actions, or violent behavior. Users of PCP often appear to be having a psychotic episode and may or may not report to the physician that they have taken the drug.


Physical Examination

In a study by McCarron et al that evaluated 1,000 patients presenting with acute phencyclidine (PCP) intoxication, clinical effects ranged from lethargy and coma to extreme agitation and psychosis. [15]

Common physical examination findings include the following:

  • Nystagmus (horizontal, vertical, or rotary) - Rotary often considered a hallmark of PCP 
  • Intoxication (57-89%)
  • Hypertension (57%)
  • Acute brain syndrome involving confusion, amnesia, disorientation, and violence (37%)
  • Agitation and violent behavior (35%)
  • Tachycardia (30%)
  • Bizarre behavior including public nudity (29%)
  • Hallucinations and delusions (19%)
  • Miosis - Often reported with a blank stare

Rare findings, usually only seen with high doses, include the following:

  • Seizures (3.1%)
  • Dystonia
  • Ataxia
  • Apnea (often seen with co-ingestants)
  • Catatonia
  • Coma - PCP coma usually presents with nystagmus and the absence of respiratory depression. Unlike opioid-induced coma, it does not improve with naloxone.
  • Hypertensive crisis
  • Myocardial infarction (non-Q wave, cardiac enzyme leak)
  • Intracranial and subarachnoid hemorrhage

Other manifestations include the following:

  • Hyperthermia, hyperreflexia, and muscle rigidity have been reported.
  • Rhabdomyolysis with or without acute kidney injury may also occur.