Which medication is an opioid antagonist?

Which medication is an opioid antagonist?

• A. Morphine
• B. Fentanyl
• C. Hydromorphone
• D. Naloxone (Narcan)

Answer: (D)

An opioid antagonist blocks opioid effects by binding to the same receptors as opioids but without activating them, effectively reversing anything caused by opioid agonists. Naloxone is the classic drug in this category. It has high affinity for mu receptors and competes with opioids like morphine, fentanyl, and hydromorphone, displacing them and rapidly reversing respiratory depression and sedation from overdose. Because it doesn’t provide analgesia and can wear off sooner than some long-acting opioids, clinicians often need to titrate the dose and may repeat administration or use an infusion. In people who are opioid-dependent, naloxone can precipitate withdrawal. The other listed medications are opioid agonists; they activate mu receptors to produce analgesia and, at higher doses, respiratory depression, not reverse it.

An opioid antagonist blocks opioid effects by binding to the same receptors as opioids but without activating them, effectively reversing anything caused by opioid agonists. Naloxone is the classic drug in this category. It has high affinity for mu receptors and competes with opioids like morphine, fentanyl, and hydromorphone, displacing them and rapidly reversing respiratory depression and sedation from overdose. Because it doesn’t provide analgesia and can wear off sooner than some long-acting opioids, clinicians often need to titrate the dose and may repeat administration or use an infusion. In people who are opioid-dependent, naloxone can precipitate withdrawal. The other listed medications are opioid agonists; they activate mu receptors to produce analgesia and, at higher doses, respiratory depression, not reverse it.