Which medication is an opioid antagonist?

Naloxone is classified as an opioid antagonist because it specifically binds to opioid receptors in the brain, blocking the effects of opioid drugs. This property makes it highly effective in reversing opioid overdoses, as it can displace opioids from these receptors and quickly restore normal breathing and consciousness in individuals who are experiencing respiratory depression due to opioid toxicity.

In contrast, hydrocodone, oxycodone, and fentanyl are all opioid agonists, meaning they activate opioid receptors to relieve pain but can also lead to suppression of the respiratory system when used inappropriately or in excess. This fundamental difference in how these medications interact with opioid receptors underlines the critical role of naloxone in emergency situations involving opioid overdose.