ritonavir
noun
ri·to·na·vir ˌrī-ˈtō-nə-ˌvir 
-ˈtä-,
ri-
: 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)
Example Sentences
Recent Examples on the Web The third pill is ritonavir, a drug first developed to help treat HIV/AIDS, which boosts the level of the first medication by slowing its breakdown in the body. 
Fionna M. D. Samuels, Scientific American, 8 Aug. 2022 Paxlovid is the brand name for the drug which is the combination of two generic medications - nirmatrelvir and ritonavir. Leada Gore | Lgore@al.com, al, 21 July 2022 Meanwhile, ritonavir inhibits cytochrome P450 (CYP) 3A4 enzymes in the liver that can break down nirmatrelvir and thus allows nirmatrelvir to hang out in your body longer. Bruce Y. Lee, Forbes, 20 May 2022 Paxlovid is actually two drugs: two of the three pills are nirmatrelvir, which stops the virus from replicating; the third pill is ritonavir, a drug once used in HIV/AIDS treatment, which boosts the effect of nirmatrelvir. Annalisa Merelli, Quartz, 18 May 2022 What is known, according to Longley and noted in other Pfizer research, is that both nirmatrelivr and ritonavir are naturally bitter — which likely is why Paxlovid is leading to a sustained bitter mouthfeel throughout treatment. Zee Krstic, Good Housekeeping, 23 May 2022 The pill is made up of two medications: ritonavir, commonly used to treat HIV and AIDS, and nirmatrelvir, an antiviral that Pfizer developed to boost the strength of the first drug. Mary Kekatos, ABC News, 9 Mar. 2022 The potential drug is designed to counter possible viral resistance to Paxlovid, and to work without the aid of the antiviral ritonavir that is given with Paxlovid but carries safety risks for patients taking some common medications. Matt Grossman, WSJ, 8 Feb. 2022 In its fact sheet about Paxlovid, the FDA has published a detailed list of medications that may interact harmfully with ritonavir, including those that should not be paired with the Covid antivirals. NBC News, 22 Dec. 2021 See More
Fionna M. D. Samuels, Scientific American, 8 Aug. 2022 Paxlovid is the brand name for the drug which is the combination of two generic medications - nirmatrelvir and ritonavir. Leada Gore | Lgore@al.com, al, 21 July 2022 Meanwhile, ritonavir inhibits cytochrome P450 (CYP) 3A4 enzymes in the liver that can break down nirmatrelvir and thus allows nirmatrelvir to hang out in your body longer. Bruce Y. Lee, Forbes, 20 May 2022 Paxlovid is actually two drugs: two of the three pills are nirmatrelvir, which stops the virus from replicating; the third pill is ritonavir, a drug once used in HIV/AIDS treatment, which boosts the effect of nirmatrelvir. Annalisa Merelli, Quartz, 18 May 2022 What is known, according to Longley and noted in other Pfizer research, is that both nirmatrelivr and ritonavir are naturally bitter — which likely is why Paxlovid is leading to a sustained bitter mouthfeel throughout treatment. Zee Krstic, Good Housekeeping, 23 May 2022 The pill is made up of two medications: ritonavir, commonly used to treat HIV and AIDS, and nirmatrelvir, an antiviral that Pfizer developed to boost the strength of the first drug. Mary Kekatos, ABC News, 9 Mar. 2022 The potential drug is designed to counter possible viral resistance to Paxlovid, and to work without the aid of the antiviral ritonavir that is given with Paxlovid but carries safety risks for patients taking some common medications. Matt Grossman, WSJ, 8 Feb. 2022 In its fact sheet about Paxlovid, the FDA has published a detailed list of medications that may interact harmfully with ritonavir, including those that should not be paired with the Covid antivirals. NBC News, 22 Dec. 2021 See More Word History
Etymology
rito- (perhaps by shortening & alteration from protease) + -navir (as in saquinavir)
First Known Use
1995, in the meaning defined above
Medical Definition
ritonavir
noun
ri·to·na·vir ˌrī-ˈtō-nə-ˌvir, -ˈtän-ə-, ri-
: a 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) see norvir