Measles ribavirin

Intravenous ribavirin decreases mortality in patients with Lassa fever and other viral hemorrhagic fevers if started early. High concentrations inhibit West Nile virus in vitro, but clinical data are lacking. Clinical benefit has been reported in cases of severe measles pneumonitis and certain encephalitides, and continuous infusion of ribavirin has decreased virus shedding in several patients with severe lower respiratory tract influenza or parainfluenza infections. At steady state, cerebrospinal fluid levels are about 70% of those in plasma. 

Ribavirin is a synthetic guanosine analogue, with in vitro activity against a broad spectrum of DNA and RNA viruses, and retroviruses, including HIV. Ribavirin has been used for treatment of a variety of viral infections, including respiratory syncytial virus bronchiolitis and pneumonia, measles, influenza types A and B, Lassa fever, hemorrhagic fever with renal syndrome (Hantaviruses), hepatitis C, and HIV infection. It is used commonly now along with interferon alpha for treatment of hepatitis C infection. There is no known direct nephrotoxicity of ribavirin. 

In the United States ribavirin has been approved (1987) only for the treatment of respiratory syncytial virus (RSV) in children, while the drug is marketed in over 20 countries for many other viral diseases. Clinical potentials of ribavirin are being evaluated against influenza, measles, AIDS, dengue, and lassa fever. 

Ribavirin is indicated in the treatment of carefully selected hospitalized infants and young children with severe lower respiratory tract infections due to respiratory syncytial virus (RSV). In addition, ribavirin (600 to 1800 mg/day for 10 to 14 days) has shown effectiveness in acute and chronic hepatitis, herpes genitalis, measles, and Lassa fever. 

Intravenous and/or aerosol ribavirin has been used occasionally in treating severe influenza virus infection and in the treatment of immunosuppressedpatients with adenovirus, vaccinia, parainfluenza, or measles virus infections. Aerosolized ribavirin reduces duration of fever but has no other beneficial effects in influenza infections in hospitalized children. Intravenous ribavirin decreases mortality in Lassa fever and has been used in treating other arenavirus-related hemorrhagic fevers. Intravenous ribavirin is beneficial in hemorrhagic fever with renal syndrome owing to hantavirus infection but ineffective in hantavirus-associated cardiopulmonary syndrome or SARS. 

Ribavirin [4.15) is of special interest because of its broad spectrum of attack. It is active against both DNA and RNA viruses. Also known as tribavirin and Virazole , this substance is l-)8-D-ribofuranosyl-l,2,4-triazole-3-carboxamide. In vivo, it is changed to the 5 -monophosphate which inhibits inosinate dehydrogenase, and hence prevents the formation of guanylic acid on which synthesis of both DNA and RNA depend. It is being used clinically for the treatment of viral pneumonia and measles although the results are not quite clear-cut (Smith and Kirkpatrick, 1980). 

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