Scientists Say: Naloxone

This live-saving drug reverses the effects of morphine, heroin and other opioids


With a prescription, people can get naloxone from a pharmacy to have in case they, or someone they know, overdoses on opioids. 

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Naloxone (noun, “Nah-LOCKS-own”)

Naloxone is a medicine that can reverse overdoses from drugs called opioids. These drugs include morphine, heroin, fentanyl and oxycodone. When taken into the body, opioids enter the brain. There they bind, or attach, to opioid receptors. These receptors are molecules in a cell membrane that control how a cell behaves. When opioids bind to them, the receptors increase or decrease the activity of the cell. This can minimize or even eliminate pain. But opioids also produce strong feelings of pleasure. That can make them very addictive.

High doses of opioids can slow breathing, enough to kill someone. That’s when a health care provider might give someone naloxone. Naloxone also binds to opioid receptors. But naloxone is an antagonist — it blocks that receptor’s normal action. By blocking opioid receptors, naloxone can reverse the effects of an opioid overdose. In some cases, this can save a person’s life.

In a sentence

Naloxone also blocks the feel-good effects that people and animals get from lying in the sun.

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Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.