Phencyclidine (PCP)-Related Psychiatric Disorders Treatment & Management
- Author: Alan D Schmetzer, MD; Chief Editor: Iqbal Ahmed, MBBS, FRCPsych(UK) more...
For good medical care of these patients, one must consider both the variability of their presentations and the risk of violence to self and/or others during the time of drug-induced psychosis. For this reason, these patients often must be admitted to a psychiatric inpatient unit for reasons of safety. In the intensive care area, where these patients may be admitted for overdoses, treatment is aimed primarily at decreased absorption by induced emesis and/or gastric lavage and charcoal. In medical or psychiatric settings, the judicious use of leather restraints may be necessary to protect these patients from harming themselves or other patients and staff members. Use of a benzodiazepine and/or an antipsychotic medicine, particularly those that are not highly anticholinergic, often help to reduce risk, but remember that risk is not entirely eliminated and may wax and wane.
- Once the diagnosis has been established, the treatment of choice generally is considered to be benzodiazepine tranquilization. Typically, diazepam is used first, unless liver damage is present. In the case of pre-existent liver damage, other benzodiazepines that do not undergo oxidative metabolism by the liver, such as lorazepam, can be administered. Starting at 10 mg, treatment consists of titrating diazepam until the patient is sufficiently sedated. Respiratory status must be monitored. Use of diazepam often decreases PCP-induced aggressiveness, psychotic symptoms, hypertension, and tachycardia.
- If psychosis remains problematic, consider the addition of an antipsychotic. In the past, this would often have been haloperidol, but now that short-acting injectable ziprasidone and olanzapine for intramuscular administration, as well as quick-dissolving olanzapine and risperidone for oral use, are available, these are generally considered to be better alternatives. When antipsychotics are necessary, always use one that is low in anticholinergic activity because of the anticholinergic properties of PCP itself.
- In the past, acidification of the urine was performed using ammonium chloride, but this generally is not recommended any longer due to the possibility of renal toxicity, metabolic acidosis, and increased risk of rhabdomyolysis.
- Keep the possibility of seizures, coma, and death in mind with higher (>100 ng/mL) levels of PCP and be prepared to support respiration if needed.
- Following acute medical stabilization, psychiatric and addiction care is indicated. The patient may require transfer to a psychiatric unit if the psychosis is not as yet under adequate control.
- Evaluate for chemical dependence once the patient is no longer psychotic, and refer him or her for treatment if appropriate. This is a serious and potentially fatal drug of abuse. Regard PCP intoxication and abuse with the same seriousness as any other potentially life-threatening condition.
- Tennant and colleagues have suggested the use of tricyclic antidepressants such as desipramine for withdrawal when dependence is present.
Obtain psychiatric consultation if the patient is in the emergency department or a general medical unit. If a separate consultation team for addictive disorders is available, ask that group to evaluate the patient. Likewise, if the patient is in a psychiatric unit or in the psychiatry emergency department, consultation with internal medicine and/or addiction subspecialists may be indicated. For people using PCP who may appear to have been injured, orthopedic or surgical consults are indicated, especially as the anesthetic nature of the substance can mask the usual discomfort of fractures and/or internal injuries rendering more casual assessments of the seriousness of the patient’s condition difficult or impossible.
Patients may require seclusion and/or restraint while acutely intoxicated with PCP. Patients who require seclusion or restraint can be highly violent and confused, and they often complain of very disturbing thoughts about harming themselves or others. Current regulations require frequent monitoring of all persons in seclusion or restraint, including a face-to-face assessment by an independent, licensed practitioner within 1 hour of initiation, and new orders every 4 hours, with additional face-to-face assessments every 8 hours. Adolescent seclusion and restraint rules are more stringent still. Suicide and assault precautions are usually necessary for these patients. When ataxia is present, do not allow ambulation of the patient to occur without assistance due to the risk of falls.
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