Naloxone is an antidote to opioid drugs. Opioids can slow or stop a person’s breathing, which causes death. Naloxone helps the person wake up and keeps them breathing.

An overdose death may happen hours after taking drugs. If a bystander acts when they first notice a person’s breathing has slowed, or when they can’t awaken a user, there is time to call 911, start rescue breathing (if needed) and give naloxone.