Which finding is commonly observed in PCP overdose?

Which finding is commonly observed in PCP overdose?

• A. Violent behavior
• B. Psychosis
• C. Nystagmus
• D. Elevated CPK

Answer: (C)

Phencyclidine (PCP) overdose classically presents with nystagmus, especially vertical nystagmus. This drug is a dissociative anesthetic that acts as an NMDA receptor antagonist, causing dissociation, perceptual distortions, agitation, and motor disturbances. The disruption of ocular motor control by PCP on brainstem circuits leads to involuntary eye movements, making nystagmus a hallmark finding. Beyond nystagmus, patients may be agitated or violent, have autonomic instability (tachycardia, hypertension, hyperthermia), ataxia, and sometimes perceptual distortions or psychosis. Elevated CPK can occur if there’s severe agitation or hyperthermia, but it is not as consistently observed as nystagmus. So, the most characteristic and commonly observed sign in PCP overdose is nystagmus, with vertical nystagmus being particularly notable.

Phencyclidine (PCP) overdose classically presents with nystagmus, especially vertical nystagmus. This drug is a dissociative anesthetic that acts as an NMDA receptor antagonist, causing dissociation, perceptual distortions, agitation, and motor disturbances. The disruption of ocular motor control by PCP on brainstem circuits leads to involuntary eye movements, making nystagmus a hallmark finding.

Beyond nystagmus, patients may be agitated or violent, have autonomic instability (tachycardia, hypertension, hyperthermia), ataxia, and sometimes perceptual distortions or psychosis. Elevated CPK can occur if there’s severe agitation or hyperthermia, but it is not as consistently observed as nystagmus.

So, the most characteristic and commonly observed sign in PCP overdose is nystagmus, with vertical nystagmus being particularly notable.