Phencyclidine Toxicity Medication
- Author: Patrick L West, MD; Chief Editor: Asim Tarabar, MD more...
Medication Summary
The goals of pharmacotherapy are to relieve the toxic effects of PCP, reduce morbidity, and prevent complications.
GI decontaminant
Class Summary
These agents prevent further absorption of adsorbable toxins from the GI tract. They are most beneficial if administered within 1-2 h of ingestion.
Activated charcoal (Liqui-Char)
Because PCP undergoes enterohepatic recirculation, may be indicted if clinically feasible. Emergency treatment in poisoning caused by drugs and chemicals. Network of pores present in activated charcoal adsorbs 100-1000 mg of drug per gram of charcoal. Does not dissolve in water.
Benzodiazepines
Class Summary
Indications include agitation, violent behavior, psychosis, seizures, and muscular rigidity.
Diazepam (Valium)
Enhances GABA transmission. Appears to act on part of the limbic system, the thalamus and hypothalamus, to induce a calming effect. Rapidly distributes to other body fat stores. Twenty minutes after initial IV infusion, serum concentration drops to 20% of Cmax.
Individualize dosage and increase cautiously to avoid adverse effects.
Lorazepam (Ativan)
Short-acting anxiolytic with relatively long half-life.
Increases transmission of GABA, a major inhibitory neurotransmitter in the brain.
May be used IV and is well absorbed after IM injection. Onset of action occurs within min of an injection, and effects peak 15-20 min after injection. Duration of action is 6-8 h. No active metabolites exist.
Midazolam (Versed)
Used as alternative in termination of refractory status epilepticus. Because water soluble, takes approximately 3 times longer than diazepam to peak EEG effects. Thus, clinician must wait 2 min to fully evaluate sedative effects before initiating procedure or repeating dose. Has twice the affinity for benzodiazepine receptors than diazepam. May be administered IM if unable to obtain vascular access.
Antihypertensives
Class Summary
These agents are used for blood pressure control in hypertensive crises to minimize end-organ damage.
Nitroprusside (Nitropress)
Produces vasodilation and increases inotropic activity of the heart. At higher dosages, may exacerbate myocardial ischemia by increasing the heart rate.
Neuroleptics
Class Summary
These agents are used for acute psychosis when no contraindications are present.
Haloperidol (Haldol)
Butyrophenone noted for high potency and low potential for causing orthostasis. Downside is high potential for EPS and dystonia. Lowers seizure threshold and worsens anticholinergic symptoms, including hyperthermia. Should be reserved only for mild PCP intoxications with predominantly psychotic features and normal vital signs.
Parenteral dosage form may be admixed with 2 mg lorazepam for better anxiolytic effects.
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