Pharmacology · single question
CASE 6 — What is the mechanism of action of naloxone?
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Correct answer: C. Mu opioid receptor antagonist
- A. NMDA agonism would cause excitatory/hallucinogenic effects.
- B. NMDA antagonists (ketamine, memantine) are used for anesthesia/Alzheimer's — unrelated to opioid reversal.
- C. Naloxone (Narcan) is a competitive mu opioid receptor ANTAGONIST. It rapidly reverses opioid overdose by displacing opioids from mu (and kappa/delta) receptors, restoring respiratory drive. The emergency reversal agent for opioid overdose.
- D. Mu opioid agonists (morphine, oxycodone) cause analgesia and respiratory depression — the opposite of naloxone's action.