Рибавирин

Химические свойства

Colourless Solid

Использование

Ribavirin is a guanosine analog with antiviral properties against DNA and RNA viruses, including respiratory syncytial virus, hepatitis C, and influenza. It acts as a prodrug that can be activated by either mono- or tri-phosphorylation by cellular kinases. These phosphorylated derivatives of ribavirin have diverse effects on both cellular and viral enzymes, resulting in suppression of viral replication.

Определение

ChEBI: A 1-ribosyltriazole that is the 1-ribofuranosyl derivative of 1,2,4-triazole-3-carboxamide. An inhibitor of HCV polymerase.

Показания

Ribavirin is a synthetic guanosine analogue that possesses broad antiviral inhibitory activity against many viruses, including influenza A and B, parainfluenza,RSV, HCV, HIV-1, and various herpesviruses, arenaviruses, and paramyxoviruses. Its exact mechanism of action has not been fully elucidated; however, it appears to inhibit the synthesis of viral mRNA through an effect on nucleotide pools. Following absorption, host cell enzymes convert ribavirin to its monophosphate, diphosphate, and triphosphate forms. Ribavirin monophosphate inhibits the guanosine triphosphate (GTP) synthesis pathway and subsequently inhibits many GTP-dependent processes. Ribavirin triphosphate inhibits the 5 capping of viral mRNA with GTP and specifically inhibits influenza virus RNA polymerase. Ribavirin may also act by increasing the mutation rate of RNA viruses, leading to the production of nonviable progeny virions. Ribavirin resistance has not been documented in clinical isolates.

Приобретенная устойчивость

Development of resistant virus strains has not been demonstrated.

Общее описание

Ribavirin is 1-β-D-ribofuranosyl-1,2,4-thiazole-3-carboxamide.The compound is a purine nucleoside analog with amodified base and a D-ribose sugar moiety.
Ribavirin inhibits the replication of a very wide variety ofRNA and DNA viruses,68 including orthomyxoviruses,paramyxoviruses, arenaviruses, bunyaviruses, herpesviruses,adenoviruses, poxvirus, vaccinia, influenza virus(types A and B), parainfluenza virus, and rhinovirus. In spiteof the broad spectrum of activity of ribavirin, the drug hasbeen approved for only one therapeutic indication—thetreatment of severe lower respiratory infections caused byRSV in carefully selected hospitalized infants and youngchildren.

Реакции воздуха и воды

Water soluble.

Профиль реактивности

Ribavirin may be sensitive to prolonged exposure to light.

Опасность

Mildly toxic by ingestion. An experimental teratogen.

Пожароопасность

Flash point data for Ribavirin are not available; however, Ribavirin is probably combustible.

Фармацевтические приложения

A synthetic nucleoside. It is neither a classic pyrimidine nor a purine, but stereochemical studies indicate that it is a guanosine analog. It is usually formulated for administration by inhalation, but oral and intravenous preparations are also used.

Механизм действия

Ribavirin, a guanosine analogue, has broad-spectrum antiviral activity against both DNA and RNA viruses. It is phosphorylated by adenosine kinase to the triphosphate, resulting in the inhibition of viral specific RNA polymerase, disrupting messenger RNA and nucleic acid synthesis.

Фармаколо?гия

Oral and intravenous ribavirin are associated with additional adverse effects.When given via these routes, ribavirin can produce hemolytic anemia that is reversible following dosage reduction or cessation of therapy. When given in combination with interferon- , ribavirin increases the incidence of many of its side effects, such as fatigue, nausea, insomnia, depression, and anemia, and may cause fatal or nonfatal pancreatitis. Ribavirin is mutagenic, teratogenic, and embryotoxic in animals at doses below the therapeutic level in humans. It is contraindicated in pregnant women and in the male partners of pregnant women. Women of childbearing potential and male partners of these women must use two effective forms of contraception during ribavirin treatment and for 6 months post therapy. Pregnant women should not directly care for patients receiving ribavirin.

Клиническое использование

Ribavirin aerosol (Virazole) is indicated in the treatment of high-risk infants and young children with severe bronchiolitis or pneumonia due to RSV infection. Treatment is most effective if begun within 3 days of the onset of symptoms.
Although ribavirin monotherapy is ineffective against HCV, oral ribavirin in combination with interferon-α (Rebatron) is approved for this indication and is effective in patients resistant to interferon therapy alone. Intravenous ribavirin may be useful in the therapy of Hantaan virus infection, Crimean or Congo virus hemorrhagic fever, Lassa fever, and severe adenovirus infection.

Побочные эффекты

Most adverse effects associated with aerosol ribavirin are local. Pulmonary function may decline if aerosol ribavirin is used in adults with chronic obstructive lung disease or asthma. Deterioration of pulmonary and cardiovascular function has also been seen in severely ill infants given this preparation. Rash, conjunctivitis, and rare cases of anemia have been reported. Health care workers exposed to aerosol ribavirin during its administration have reported adverse effects including headache, conjunctivitis, rash, and rarely, bronchospasm.