Favipiravir (T-705) sodium is an inhibitor of viral RNA polymerase ( RNA polymerase ), which is converted into its active form Favipiravir-ribofuranosyl-5′-triphosphate (RTP). Favipiravir-RTP inhibits the activity of influenza virus RNA-dependent RNA polymerase ( RdRP ) with an IC 50 of 341 nM.