osel·​tam·​i·​vir ˌō-ˌsel-ˈta-mə-ˌvir How to pronounce oseltamivir (audio)
: an antiviral drug that is taken orally in the form of its phosphate C16H28N2O4·H3PO4 and is a neuraminidase inhibitor used in the treatment and prevention of influenza A and B
The current countermeasures against seasonal influenza are the use of annual vaccines and antiviral drugs, such as oseltamivir.Charles J. Russell
Research has shown that taking a prescription antiviral, such as oseltamivir or zanamivir, in the first 48 hours after contracting the flu virus can speed recovery.Francesca Castagnoli

Examples of oseltamivir in a Sentence

Recent Examples on the Web Antiviral drugs that treat variant flu infections in humans are oseltamivir (Tamiflu), zanamivir (Relenza) and peramivir (Rapivab). Cnn Editorial Research, CNN, 6 June 2021 Drugs like oseltamivir inhibit the spread of viral infection in a host by blocking the neuraminidase. Gemma Tarlach, Discover Magazine, 10 Dec. 2013

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

Word History


oselt- (of undetermined origin) + -ami-, infix denoting a neuraminidase inhibitor (from neuraminidase) + -vir, combining element denoting an antiviral compound (from virus)

Note: According to the prescriptions of the U.S. Adopted Names Council, the initial element in generic drug names is to be meaningless.

First Known Use

1998, in the meaning defined above

Time Traveler
The first known use of oseltamivir was in 1998

Dictionary Entries Near oseltamivir

Cite this Entry

“Oseltamivir.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/oseltamivir. Accessed 23 Feb. 2024.

Medical Definition


osel·​tam·​i·​vir ˌō-ˌsel-ˈtam-ə-ˌvir How to pronounce oseltamivir (audio)
: an antiviral drug administered orally in the form of its phosphate C16H28N2O4·H3PO4 in the treatment and prevention of influenza A and B
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