What is naloxone and how does it reverse opioid overdose?

Naloxone, brand name Narcan, is an opioid antagonist that rapidly reverses opioid overdose by competitively binding to opioid receptors and displacing the opioid molecule. It is administered intranasally, intramuscularly, or intravenously, with effects beginning within two to five minutes. Naloxone reverses respiratory depression, sedation, and hypotension caused by opioid overdose. Its duration of action is 30 to 90 minutes, which is shorter than most opioids, so patients may require repeated doses or continuous monitoring as the naloxone wears off.