Naloxone is a life-saving medication used to reverse an opioid overdose, including heroin, fentanyl and prescription opioid medications. Naloxone can be quickly given through nasal spray (Narcan®) in the nose, or through an injectable or auto-injector into the outer thigh or another major muscle. Naloxone is safe and easy to use, works almost immediately, and is not addictive. Naloxone has very few negative effects, and has no effect if opioids are not in a person’s system.