Opioid use disorder — MCCQE Part 1 MCQ

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HardSubstance UseOpioid use disorderMCCQE Part 1

An unresponsive person has slow shallow breathing, pinpoint pupils, bradycardia, and hypotension after using an unregulated drug reported to contain fentanyl and xylazine. What is the most appropriate immediate response?

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Correct answer: A — Give naloxone, support ventilation, and activate emergency care

Naloxone should be given because fentanyl is suspected and reversing the opioid component can restore ventilation. Xylazine is not an opioid and its sedation, bradycardia, or hypotension will not respond to naloxone, so airway positioning, oxygenation, assisted ventilation, circulation support, and emergency transport remain essential even if pupils or consciousness do not fully normalise. Additional naloxone may be required for persistent opioid-mediated respiratory depression, but repeatedly dosing naloxone cannot substitute for ventilation when non-opioid sedation persists. Toxicology results must not delay resuscitation. Flumazenil reverses selected benzodiazepines and can provoke seizures; it has no role as a xylazine antidote.

Reference: Health Canada, Overdose Crisis and the Toxic Illegal Drug Supply: https://www.canada.ca/en/health-canada/services/opioids/overdose-crisis-toxic-illegal-drug-supply.html