Phencyclidine toxicity

Note: this page is about the drug phencyclidine. For the infection, see PCP pneumonia

Background

PCP in several forms.

• Also known as: PCP, "angel dust", "dippers", "supergrass", "whack", "rocket fuel"
• Synthetic piperidine derivative, structurally similar to ketamine
• NMDA inhibitor, at high doses, can also act as norepinepherine/dopamine reuptake inhibitor, and interact with opioid, acetylcholine, and voltage-gated ion channel receptors
• Dissociative anesthetic
• Smoked, ingested, or injected
• Sometimes combined with tobacco, marijuana ("wet"), crack cocaine, or other drugs

Hallucinogen, designer drug, and club drug toxicities

• Serotonin-Like Agents
  • Lysergic acid diethylamide toxicity (LSD)
  • Psilocybin toxicity ("magic mushrooms")
  • N,N-Dimethyltryptamine toxicity (DMT)
  • 5-methoxy- dimethyltryptamine (5-MeO-DMT)
  • 25C-NBOMe toxicity
• Enactogens
  • Designer amphetamines
  • Bath salts toxicity
  • Ecstasy (MDMA) toxicity
  • Mescaline toxicity (peyote)
  • Synthetic cannabinoid toxicity
• Dissociative Agents
  • Phencyclidine toxicity (PCP)
  • Ketamine
  • Dextromethorphan toxicity
  • Nitrous oxide toxicity
• Plant-based Hallucinogenics
  • Marijuana toxicity
  • Salvia toxicity
  • Absinthe toxicity
  • Isoxazole Mushrooms
  • Hawaiian baby woodrose (Argyreia nervosa)
  • Hawaiian woodrose (Merremia tuberosa)
  • Morning glory (Ipomoea violacea)
  • Olili- uqui (Rivea corymbosa)

Clinical Features

• Onset/duration of action dependant on route of administration; onset usually ~5 minutes if snorted, usually lasts 4-6 hours but can be longer if high dose
• Symptoms can fluctuate from CNS depression to excitation
• Wide range of symptoms due to PCP's cholinergic, anticholinergic, and sympathomimetic properties
  • Nystagmus (very common), ataxia
  • Hypertension, hypertensive crisis
  • Dissociation
  • Feelings of strength, invulnerability, hallucinations
  • Agitation, unpredictable behavior, violence
  • Tachycardia
  • Dystonia, muscle rigidity
  • Hyperthermia
• Excited delirium
  • Seizure
  • Coma or apparent comatose state (if very dissociated)

Differential Diagnosis

Drugs of abuse

• 25C-NBOMe‎
• Alcohol
• Amphetamines
• Bath salts
• Cocaine
• Difluoroethane
• Ecstasy
• Gamma hydroxybutyrate (GHB)
• Heroin
• Inhalant abuse
  • Hydrocarbon toxicity
  • Difluoroethane (electronics duster)
• Marijuana
• Kratom
• Phencyclidine (PCP)
• Psilocybin ("magic mushrooms")
• Synthetic cannabinoids
• Chloral hydrate
• Body packing

Movement Disorders and Other Abnormal Contractions

• Chorea
  • Sydenham's chorea
• Neuroleptic malignant syndrome
• Serotonin syndrome
• Hypocalcemia
• Strychnine toxicity
• Acute tetanus
• Parkinson's disease
• Mono amine oxidase inhibitor toxicity
• Phencyclidine toxicity
• Anti-NMDA receptor encephalitis
• Huntington disease
• Wilson's disease
• CVA
• Schizophrenia
• Psychotic agitation
• Dementia
  • Lewy body dementia
  • Vascular dementia
  • Frontotemporal dementia
• Dystonic reaction
• Extrapyramidal reaction
• Torticollis
• Idiopathic movement disorder

Evaluation

Diagnosis

• Usually clinical diagnosis
• UDS: false positive screens for PCP can result from dextromethorphan, diphenhydramine, doxylamine, ibuprofen, meperidine, tramadol, venlafaxine)
• Evaluate for dangerous effects of drug:
  • Occult trauma
  • Rhabdomyolysis
  • Hypoglycemia
  • Hepatic injury due to hyperthermia
  • End-organ damage due to hypertensive emergency
• Evaluate for other causes of presentation (e.g. other drugs, infection, endocrine/metabolic disorders, other causes of AMS)

Toxidrome Chart

Finding	Cholinergic	Anticholinergic	Sympathomimetic	Sympatholytic^	Sedative/Hypnotic
Example	Organophosphates	TCAs	Cocaine	Clonidine	ETOH
Temp	Nl	Nl / ↑	Nl / ↑	Nl / ↓	Nl / ↓
RR	Variable	Nl / ↓	Variable	Nl / ↓	Nl / ↓
HR	Variable	↑	↑ (sig)	Nl / ↓	Nl / ↓
BP	↑	↑	↑	Nl / ↓	Nl / ↓
LOC	Nl / Lethargic	Nl, agitated, psychotic, comatose	Nl, agitated, psychotic	Nl, Lethargic, or Comatose	Nl, Lethargic, or Comatose
Pupils	Variable	Mydriatic	Mydriatic	Nl / Miotic
Motor	Fasciculations, Flacid Paralysis	Nl	Nl / Agitated	Nl
Skin	Sweating (sig)	Hot, dry	Sweating	Dry
Lungs	Bronchospasm / rhinorrhea	Nl	Nl	Nl
Bowel Sounds	Hyperactive (SLUDGE)	↓ / Absent	Nl / ↓	Nl / ↓

^Consider Sympatholytic when looking at Sedative OD or someone who doesn't respond to Narcan

Withdrawal from substances have the opposite effect

Management

• Physical restraints only if danger to self and others
• Sedation: IV benzodiazepines
• Seizures: benzodiazepines, may require propofol and intubation for status epilepticus
• Active cooling if hyperthermic
• Hypertension: usually responds to benzos, but can use nitroprusside if severe/refractory
• IV fluids for rhabdomyolysis

Disposition

• Discharge if only minor medical complications and behavior normalizes

See Also

• Sympathomimetic toxicity
• Drugs of abuse
• Hallucinogens
• Excited delirium