Favipiravir, sold under the brand name Avigan among others, is an antiviral medication used to treat influenza in Japan. It is also being studied to treat a number of other viral infections, including SARS-CoV-2. Like the experimental antiviral drugs T-1105 and T-1106, it is a pyrazinecarboxamide derivative.
It is being developed and manufactured by Toyama Chemical (a subsidiary of Fujifilm) and was approved for medical use in Japan in 2014. In 2016, Fujifilm licensed it to Zhejiang Hisun Pharmaceutical Co. It became a generic drug in 2019.