Ribavirin is a guanosine (ribonucleic) analog used to stop viral RNA synthesis and viral mRNA capping, thus, it is a nucleoside inhibitor.Its brand names include Copegus, Rebetol, Ribasphere, Vilona, and Virazole.either of these mechanisms explains ribavirin's effect on many DNA viruses, which is more of a mystery, especially given the complete inactivity of ribavirin's 2' deoxyribose analogue, which suggests that the drug functions only as an RNA nucleoside mimic, and never a DNA nucleoside mimic.