Ribavirin

Ribavirin inhibits the replication of a wide range of DNA and RNA viruses, including influenza A and B, parainfluenza, respiratory syncytial virus (RSV), paramyxoviruses, HCV, and HIV. Although the precise antiviral mechanism of ribavirin is not known, the drug inhibits guanosine triphosphate formation, prevents capping of viral mRNA, and can block RNAdependent RNA polymerases. Ribavirin is effective orally (avoid antacids) and is also available in intravenous and aerosol forms.It is eliminated by the kidney, necessitating dose reductions in renal dysfunction. Ribavirin is used adjunctively with IFN-α in chronic HCV infection in patients with compensated liver disease.Monotherapy with ribavirin alone is not effective. Early intravenous administration of ribavirin decreases mortality in viral hemorrhagic fevers.Despite its alleged activity against RSV it is still recommended by some authorities in immunocompromised children.Ribavirin is also effective in chronic hepatitis C infections when used in combination with interferon-α. Ribavirin may reduce the mortality and viremia of Lassa fever. The drug is first converted to the 5’-phosphate derivatives, the major product being the compound ribavirin-triphosphate, which exerts its antiviral action by inhibiting guanosine triphosphate formation, preventing viral messenger RNA (mRNA) capping, and blocking RNA-dependent RNA polymerase.[Note: Rhinoviruses and enteroviruses, which contain preformed mRNA and do not need to synthesize mRNA in the host cell to initiate an infection, are relatively resistant to the action of ribavirin.] Ribavirin is effective orally and intravenously.Absorption is increased if the drug is taken with a fatty meal. An aerosol is used in certain respiratory viral conditions such as the treatment of RSV infection.NO CNS