Favipiravir

ABSTRACT

Favipiravir (6-Fluoro-3-hydroxypyrazine-2-carboxamide), a purine nucleic acid analog that has been developed by Toyama Chemical in Japan for a treatment of viral infections including influenza.3 This has recently been evaluated and was found to be a promising choice in management of COVID-19. It works by inhibiting RNA dependent RNA polymerase (RdRp) enzyme, a key enzyme impeding replication of RNA viruses. Favipiravir is a pro-drug that is ribosylated and phosphorylated intracellularly to form the active metabolite Favipiravir ribofuranosyl-5'-triphosphate (Favipiravir- RTP). Favipiravir -RTP competes with purine nucleosides and interferes with viral replication by incorporating into the nascent viral RNA triggering inhibition of error-prone viral RdRp, leading to Chain termination and Viral mutagenesis. Favipiravir is a pro-drug that is ribosylated and phosphorylated intracellularly to form the active metabolite Favipiravir ribofuranosyl-5'-triphosphate (Favipiravir- RTP). Majority (~ 80-85%) of COVID-19 patients suffer from mild to moderate illness and continue to spread the virus. Favipiravir which is indicated in treatment of mild to moderate cases promises to reduce the burden of this ongoing pandemic.