Favipiravir

Favipiravir is an antiviral drug that targets viral RNA-dependent RNA polymerase. It is approved for influenza treatment in some countries and has also been studied against other RNA viruses.

RNA-dependent RNA polymerase: An enzyme that copies RNA from an RNA template, enabling replication of many RNA viruses. Favipiravir’s active form interferes with this enzyme during viral genome replication.
Influenza: A contagious respiratory illness caused by influenza viruses. Favipiravir was developed and approved in some countries for influenza treatment.
Toyama Chemical: A Japanese pharmaceutical company that discovered and developed favipiravir. The compound emerged from this company’s antiviral research program.
Teratogenicity: The capacity of an exposure to cause developmental abnormalities in an embryo or fetus. Animal findings led to strict pregnancy-related restrictions on favipiravir.
Favipiravir ribofuranosyl-5′-triphosphate: The phosphorylated intracellular form of favipiravir that can be incorporated into viral RNA. This metabolite, rather than the administered drug itself, engages viral polymerase.
Avigan: A Japanese brand name for favipiravir, marketed for restricted use against influenza. The brand illustrates favipiravir’s limited, country-specific influenza authorization.
Influenza antiviral drug development: The research and testing process that produces medicines intended to prevent or treat influenza. Favipiravir followed a distinctive development path through preclinical work and restricted approval.
Favipiravir resistance: Reduced susceptibility to favipiravir caused by viral changes that lessen its antiviral effect. Polymerase mutations can alter viral sensitivity and complicate repeated or widespread use.
Lethal mutagenesis: A proposed antiviral strategy that drives viral mutation rates high enough to impair replication or survival. Favipiravir incorporation can promote mutations that undermine viral populations.
COVID-19 drug repurposing: The evaluation of existing medicines as potential treatments for COVID-19. Favipiravir was widely tested during the pandemic, but evidence did not establish routine benefit.

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RemdesivirCompared with: It is another polymerase-targeting antiviral, but its approved uses and evidence differ.