FMGE 2025 — Pharmacology

Q: A patient is brought to the emergency department with signs suggesting opioid poisoning. What is the antidote of choice?

Naloxone. ***Naloxone***- **Naloxone** is the drug of choice for treating opioid poisoning, acting as a competitive antagonist at **mu**, kappa, and delta opioid receptors [1]. - It reverses the life-threatening effects of opioid overdose, primarily **respiratory depression** and **central nervous system depression**, within minutes of administration [3].*Flumazenil*- Flumazenil is the specific antagonist used to reverse the effects of **benzodiazepine overdose**, acting at the GABA-A receptor.- It is generally ineffective and not indicated for pure opioid toxicity.*Atropine*- Atropine is an **anticholinergic agent** used primarily in the treatment of symptomatic **bradycardia** and **organophosphate poisoning** [2].- It does not antagonize opioid receptors and has no direct role in reversing opioid-induced respiratory depression.*Physostigmine*- Physostigmine is a **reversible acetylcholinesterase inhibitor** used mainly for reversing severe central nervous system effects of **anticholinergic poisoning** (e.g., tricyclic antidepressants).- Increasing acetylcholine is irrelevant and potentially counterproductive in treating opioid-induced respiratory depression.

31 Questions — Page 4 of 4

Q31

A patient is brought to the emergency department with signs suggesting opioid poisoning. What is the antidote of choice?