Favipravir
This viral polymerase inhibitor is approved, in Japan, for the treatment
of novel strains of the influenza virus unresponsive to current
antivirals. Its activity spectrum spreads across A, B and C strains of
the virus. Favipravir becomes active after ribosylation and
phosphorylation. This triphosphorylated favipravir competitively inhibit
the viral RNA-dependent RNA polymerase (RdRp) of influenza virus known
as polymerase basic 1 transcriptase thereby interfering with the viral
replication (Hayden & Shindo, 2019; Beigel et al., 2019; Principi et
al., 2019; Furuta et al., 2013; Madelain et al., 2016).
Favipravir is well tolerated clinically but the adverse effects that can
be associated with its use include diarrhoea, teratogenicity, increased
serum uric acid levels, elevated levels of transaminases, reduced
neutrophil counts (Hayden & Shindo, 2019; Principi et al., 2019;
Madelain et al., 2016).