Favipiravir is an anti-viral drug capable of inhibiting the RNA-dependent RNA polymerase (RdRp) of RNA viruses. The official chemical name of Favipiravir is T-705; 6-fluoro-3-hydroxy-2-pyrazinecarboxamide. It was discovered by Toyama Chemical Co., Ltd during experiments held by the company for finding chemical compounds capable of exhibiting anti-viral activity against influenza viruses.
Favipiravir must undergo phosphoribosylation inside of cells (intracellular) to become it's active form called favipiravir-RTP (favipiravir ribofuranosyl-5'-triphosphate). Research suggests Favipiravir exhibits a broad spectrum of anti-viral activity towards RNA viruses due to it's mechanism of action, and is effective for treating a wide range of types and sub-types of RNA influenza viruses, including strains typically showing resistance to anti-influenza drugs, which include: arenaviruses, bunyaviruses and filoviruses.
Favipiravir-RTP (the active form of Favipiravir) is able to become incorporated in viral RNA (vRNA), and may act as a binding agent on vRNA conserved polymerase domains which prevents the ability of vRNA to use the cellular machinery of its host organism required for its own replication and transcription. This mechanism of action is what is thought to give Favipiravir its anti-viral properties.