naloxone

noun

nal·​ox·​one na-ˈläk-ˌsōn How to pronounce naloxone (audio)
: a synthetic potent antagonist of narcotic drugs (such as morphine and fentanyl) that is administered especially in the form of its hydrochloride C19H21NO4·HCl

Note: Naloxone is administered by injection or as a nasal spray to reverse the effects of opioids especially in the emergency treatment of opioid overdose. It is also administered in combination with buprenorphine in the form of a dissolvable tablet placed under the tongue or a film placed inside the cheek to treat opioid dependence.

Examples of naloxone in a Sentence

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Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
For example, when the medication is taken as directed, under the tongue or inside the cheek, relatively little naloxone reaches the bloodstream. — Encyclopedia Britannica, 28 Aug. 2026 If preban trends had continued, there would have been over 150 naloxone kits distributed weekly by one program, on average. — Paul Christine, The Conversation, 25 Aug. 2026 All five inmates affected were administered two doses of naloxone (Narcan) to reverse the overdose effects, the office said. — Carlos E. Castañeda, CBS News, 17 Aug. 2026 Jail staff began lifesaving measures and administered naloxone, commonly known by the brand name Narcan, which can reverse an opioid overdose. — Sacramento Bee Contributor, Sacbee.com, 17 Aug. 2026 See All Example Sentences for naloxone

Word History

Etymology

N-allyl + hydroxy- + -one

First Known Use

1964, in the meaning defined above

Time Traveler
The first known use of naloxone was in 1964

Rhymes for naloxone

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Browse Nearby Words

nalorphine
naloxone
naltrexone
See all Nearby Words

Cite this Entry

“Naloxone.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/naloxone. Accessed 2 Sep. 2026.

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Medical Definition

naloxone

noun
nal·​ox·​one nal-ˈäk-ˌsōn How to pronounce naloxone (audio) ˈnal-ək-ˌsōn How to pronounce naloxone (audio)
: a potent synthetic antagonist of narcotic drugs (as morphine and fentanyl) that is administered especially in the form of its hydrochloride C19H21NO4·HCl

Note: Naloxone is administered by injection or as a nasal spray to reverse the effects of opioids and especially in the emergency treatment of opioid overdose. It is also administered in combination with buprenorphine in the form of a dissolvable tablet placed under the tongue or a film placed inside the cheek to treat opioid dependence. Trademarks for preparations containing naloxone include Bunavail, Evzio, Narcan, Suboxone, and Zubsolv.

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