favipiravir + hydroxychloroquine

A combination therapy consisting of favipiravir and hydroxychloroquine that was investigated for the treatment of COVID-19. Favipiravir is a purine nucleoside analog that selectively inhibits RNA-dependent RNA polymerase (RdRp), preventing viral genome replication. Hydroxychloroquine works by increasing endosomal pH, preventing ACE2 receptor glycosylation, blocking sialic acid receptors, and exerting immunomodulatory effects that reduce cytokine production. Clinical studies showed this combination had efficacy in reducing viral load and hospitalization rates in COVID-19 patients, though with varying side effect profiles.