Elevated CPK levels are most commonly associated with which overdose presentation?

• A. Alcohol withdrawal
• B. PCP overdose
• C. Opioid overdose
• D. Benzodiazepine overdose

Answer: (B)

Elevated CPK signals muscle breakdown from rhabdomyolysis. This is most likely when there is prolonged, intense muscle activity or rigidity, as seen with phencyclidine (PCP) intoxication, which often causes severe agitation, combativeness, hyperthermia, and sustained movement. That combination can rapidly drive rhabdomyolysis and dramatically raise CPK levels. In contrast, opioid and benzodiazepine overdoses tend to cause CNS depression with reduced movement, and alcohol withdrawal can involve autonomic hyperactivity or seizures but is less characteristically associated with marked rhabdomyolysis and huge CPK elevations unless complications develop. Thus PCP overdose best explains the scenario of elevated CPK.