Phencyclidine (PCP)-Related Psychiatric Disorders Medication

Updated: Feb 14, 2018
  • Author: Jeffrey S Forrest, MD; Chief Editor: Ana Hategan, MD, FRCPC  more...
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Medication

Medication Summary

Benzodiazepines are the medication of choice when treating acute PCP intoxication.

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Benzodiazepines

Class Summary

Treat symptoms of aggressivity and may decrease the likelihood of seizures and psychotic complications in PCP intoxication.

Lorazepam (Ativan)

DOC; may be used IV and is well-absorbed after IM injection. Onset of action occurs within minutes of an injection and effects peak 15-20 minutes after injection. Duration of action is 6-8 h. No active metabolites exist.

Diazepam (Valium, Diastat)

Historically, this medication has been the most helpful benzodiazepine in treating acute PCP intoxication. Even the psychotic symptoms respond sometimes. Diazepam is not absorbed reliably IM, but it can be administered both PO and IV. If IV administration is contemplated, decrease dose and be prepared to treat possible respiratory depression. If IM route is used, consider lorazepam as alternative, with dosage range of 1-2 mg.

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Antipsychotic agents

Class Summary

These agents are useful when PCP-induced psychotic symptoms do not respond adequately to benzodiazepines or when benzodiazepines are contraindicated. Avoid using highly anticholinergic antipsychotics because PCP is fairly anticholinergic.

Risperidone (Risperdal)

Atypical antipsychotic medication. Has lower incidence of extrapyramidal adverse effects than traditional neuroleptics, such as haloperidol. Binds to dopamine D2 receptor with 20 times lower affinity than for 5-HT2 receptor. Improves negative symptoms of psychosis and reduces incidence of extrapyramidal adverse effects. Similarly, other newer atypical antipsychotics, such as olanzapine or quetiapine, may also be effective. Risperidone has a quick-dissolving oral formulation, Risperdal M-Tab.

Ziprasidone (Geodon)

Available in tab and a parenteral form.

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