Naloxone is a medication that is used to reverse the effects of opioids, such as heroin, fentanyl, and prescription pain medications like oxycodone and hydrocodone. Naloxone works by blocking the opioid receptors in the brain, which helps to reverse the respiratory depression and other effects of opioids.

When a person takes an opioid, the drug binds to the opioid receptors in the brain and causes the person to feel pain relief, euphoria, and other effects. However, opioids also depress the respiratory system, which can lead to slowed breathing and even respiratory arrest, which can be fatal.

Naloxone binds to the same opioid receptors as opioids, but it does not activate them in the same way. Instead, it blocks the opioids from binding to the receptors and thereby reverses the effects of the opioid. Naloxone can be administered as an injection, a nasal spray, or an auto-injector, and it is typically given by first responders, emergency medical personnel, or friends and family members of people who use opioids.