Ribavirin is a synthetic nucleoside analogue, which was first discovered and developed in 1970 by researchers from the International Chemical & Nuclear Corporation (ICN), today known as Valeant Pharmaceuticals. Ribavirin was initially approved for use in humans to treat pediatric respiratory syncytial virus infections (RSV). In cell cultures the inhibitory activity of ribavirin for RSV is selective. The mechanism of action is unknown. Reversal of the in vitro antiviral activity by guanosine or xanthosine suggests ribavirin may act as an analogue of these cellular metabolites. There were no other significant advancements in the treatment of hepatitis C until 1998, when the combination of ribavirin and interferon-alpha gained approval. Clinically, ribavirin showed a small, additive antiviral effect in combination with interferon, but its main effect was dose-dependent prevention of virological relapse. The mechanism by which the combination of ribavirin and an interferon product exerts its effects against the hepatitis C virus has not been fully established. However, it could be thorough the inhibition of inosine monophosphate dehydrogenase (IMPDH), which is the key step in de novo guanine synthesis, a requirement for viral replication.

Ribavirin elaidate (CP-4033; TRX-201), a Lipid Vector Technology derivative of ribavirin. It inhibits elongation factor F4E (elF4E), which stimulates cell growth. Translational Therapeutics Inc. received orphan drug status from the U.S. Food and Drug Administration (FDA) in 2011 for ribavirin elaidate in the treatment of aggressive follicular, medullary and anaplastic thyroid carcinoma.

α-Ribavirin is an alpha-anomer of ribavirin, a broad spectrum antiviral nucleoside. It is unnatural minor impurity of ribavirin.