Naloxone is an opioid antagonist that is a safe and effective agent for reversing the effects of pharmaceutical opioids (e.g., methadone, codeine, fentanyl and morphine) and illicit opioids (e.g., heroin and nitazenes).

Naloxone is often administered by medical personnel, including paramedics, in the event of an opioid overdose. It is also available as an intramuscular injection or intranasal spray formulation that can be purchased at pharmacies in Australia and administered to someone experiencing an opioid overdose.