ri·​to·​na·​vir ˌrī-ˈtō-nə-ˌvir How to pronounce ritonavir (audio)
: an antiviral drug C37H48N6O5S2 that is a protease inhibitor administered orally in conjunction with other agents to treat viral infections (such as HIV infection and hepatitis C)

Examples of ritonavir in a Sentence

Recent Examples on the Web The treatment consists of two medications: nirmatrelvir, which blocks a key enzyme that the Covid virus needs to replicate, and ritonavir, which boosts the first medication’s ability to fight the infection. Annika Kim Constantino, NBC News, 25 May 2023 The treatment is made up of two medications: ritonavir, commonly used to treat HIV and AIDS but which helps boost levels of other antiviral medications, and nirmatrelvir, an antiviral that works to inhibit an enzyme the virus uses to make copies of itself. Mary Kekatos, ABC News, 21 July 2022 Paxlovid combines two antiviral drugs: nirmatrelvir and ritonavir. Amanda Sealy, CNN, 9 Mar. 2022 One is designed to block the action of a key enzyme that the coronavirus uses to make copies of itself; the other, the HIV medication ritonavir, helps slow the breakdown of the first, enabling it to remain active in the body for longer and at higher concentrations. John Lauerman, Fortune, 15 Feb. 2022 Those who are prescribed Paxlovid—which includes two separate, generic drugs, nirmatrelvir and ritonavir—take three pills by mouth twice daily for five days. Korin Miller, SELF, 28 Feb. 2023 The medication should not be taken by people with severe liver or kidney disease or those who are allergic to either nirmatrelvir or ritonavir, according to the Food and Drug Administration authorization. Karen Weintraub, USA TODAY, 5 Feb. 2023 Or those who rebound may be part of the minority of people who don’t experience the right rate of drug release with the combination of nirmatrelvir and ritonavir. Fionna M. D. Samuels, Scientific American, 8 Aug. 2022 Two of the pills are an experimental antiviral called nirmatrelvir; the third pill is an existing HIV drug called ritonavir. NBC News, 14 Dec. 2021 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'ritonavir.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


rito- (perhaps by shortening & alteration from protease) + -navir (as in saquinavir)

First Known Use

1995, in the meaning defined above

Time Traveler
The first known use of ritonavir was in 1995

Dictionary Entries Near ritonavir

Cite this Entry

“Ritonavir.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ritonavir. Accessed 9 Dec. 2023.

Medical Definition


: a protease inhibitor C37H48N6O5S2 that is administered orally in conjunction with other agents (such as lopinavir or nirmatrelvir) to treat viral infections (such as HIV infection, hepatitis C, or COVID-19)

Note: Trademarks for preparations containing ritonavir include Norvir and Paxlovid.

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