In 1966, the U.S. Food and Drug Administration (FDA) licensed amantadine (marketed as Symmetrel) to Du Pont, a new antiviral medication, as a prophylactic (preventive medicine) against influenza A. It was not effective against influenza B.

Amantadine is no longer recommended for treatmen of influenza A in the U.S. The Centers for Disease Control and Prevention found 100% of seasonal H3N2 and 2009 pandemic flu samples were resistant to adamantanes (amantadine and rimantadine) during the 2008-2009 flu season.