favipiravir

Favipiravir is a small molecule antiviral drug, originally developed by Toyama Chemical (a subsidiary of Fujifilm) in Japan. It is a pyrazinecarboxamide derivative and functions as a prodrug that is metabolized to its active form, favipiravir-ribofuranosyl 5'-triphosphate (favipiravir-RTP). The primary mechanism of action involves selective inhibition of viral RNA-dependent RNA polymerase (RdRp), an enzyme essential for the transcription and replication of viral genomes. By mimicking guanosine and adenosine nucleobases, favipiravir-RTP competes with purine nucleosides for RdRp binding, leading to premature termination or lethal mutagenesis during viral RNA synthesis. Favipiravir has been approved in Japan since 2014 for the treatment of novel or pandemic influenza strains unresponsive to standard therapies and has been used off-label or under emergency use authorizations in several countries for COVID‑19. It also demonstrates broad-spectrum activity against other RNA viruses such as Ebola virus, Lassa virus, West Nile virus, arenavirus, bunyavirus, filovirus, foot-and-mouth disease virus, and SARS-CoV‑2[1][2][3][4][5][8].

Brand names

AviganFabifluPancovirFavijajFerawellFavilabBALflu

Other names

FapilavirFavilavir6-fluoro-3-hydroxy-pyrazinecarboxamide