Which triad characterizes acute opioid overdose?

• A Coma, pinpoint pupils, respiratory depression ✓
• B Coma, dilated pupils, tachycardia
• C Agitation, mydriasis, hyperthermia
• D Coma, bradycardia, hypertension

Explanation

The classic opioid toxidrome is the triad of coma, miosis (pinpoint pupils), and respiratory depression. Miosis results from mu-receptor mediated stimulation of the Edinger-Westphal nucleus, and this sign is relatively resistant to tolerance. Mydriasis points instead toward sympathomimetics, anticholinergics, or withdrawal, which kills option B. Respiratory depression remains the commonest direct cause of death in opioid overdose.

Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.

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