Oseltamivir(GS 4104; GOP-A-Flu; GS 4104; Tamiflu-Free; Tamvir) is an antiviral drug. GS 4104; GOP-A-Flu; GS 4104; Tamiflu-Free; Tamvir slows the spread of influenza (flu) virus between cells in the body by stopping the virus from chemically cutting ties with its host cell; median time to symptom alleviation is reduced by 0.5–1 day. GS 4104; GOP-A-Flu; GS 4104; Tamiflu-Free; Tamvir is marketed under the trade name Tamiflu, and is taken orally in capsules or as a suspension. It has been used to treat and prevent influenza A virus and influenza B virus infection in over 50 million people since 1999. Oseltamivir(GS 4104; GOP-A-Flu; GS 4104; Tamiflu-Free; Tamvir) is useful for Antiviral agents