Phencyclidine toxicity
Revision as of 14:37, 22 September 2016 by ClaireLewis (talk | contribs)
Note: this page is about the drug phencyclidine. For the infection, see PCP pneumonia
Background
- aka 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
- Smoked, ingested, or injected
- Sometimes combined with tobacco, marijuana ("wet"), crack cocaine, or other drugs
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
Evaluation
- Usually clinical diagnosis
- UDS: false positive screens for PCP can result from dextromethorphan, diphenydramine, 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)
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