What is the reversal agent for opioids?

• A. Naltrexone
• B. Flumazenil
• C. Naloxone
• D. Physostigmine

Answer: (C)

Naloxone is the reversal agent for opioids. It acts as a competitive antagonist at opioid receptors, especially the mu receptor, displacing opioid agonists and rapidly reversing respiratory depression and CNS depression seen in overdose. Its effects come on quickly when given by IV, and because it has a shorter duration than many opioids, repeated dosing or an infusion may be needed for long-acting opioids to maintain reversal. Naltrexone can block opioids as well but is longer-acting, usually oral, and not suited for emergency reversal because it won’t reliably reverse acutely and can precipitate withdrawal. Flumazenil reverses benzodiazepines, not opioids, and physostigmine addresses anticholinergic toxicity. So for acute opioid overdose, naloxone is the best choice.