Lassa fever ribavirin

Unlabeled u.ses of ribavirin include aerosol treatment of influenza types A and B and oral treatment of hepatitis, genital herpes, and Lassa fever. Ribavirin does not protect cells again.st the cytotoxic effects of the AIDS virus. 

Although the term nucleoside was once limited to the compounds in Table 28.2 and a few others, cunent use is more permissive. Pyrimidine derivatives of D-arabinose, for exfflnple, occur in the free state in certain sponges and are called spongonticleosides. The powerful antiviral drug ribavirin, used to treat hepatitis C and Lassa fever, is a synthetic nucleoside analog in which the base, rather than being a pyrimidine or purine, is a triazole. 

Drugs Available Prophylactic ribavirin may be effective for Crimean-Congo hemorrhagic fever, Lassa fever, and Rift Valley fever. 

Although ribavirin monotherapy is ineffective against HCV, oral ribavirin in combination with inter-feron-a (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. 

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. 

Antiviral spectrum Ribavirin is used in treating infants and young children infected with severe RSV infections. [Note It is not indicated for use in adults.] Favorable responses of acute hepatitis A virus and influenza A and B infections have also been reported. Ribavirin may reduce the mortality and viremia of Lassa fever. 

Adverse effects Side effects reported for oral or parenteral use of ribavirin have included dose-dependent transient anemia in Lassa fever victims. Elevated bilirubin has been reported. The aerosol may be safer, although respiratory function in infants can deteriorate quickly after initiation of aerosol treatment and therefore, monitoring is essential. Because of teratogenic effects in experimental animals, ribavirin is contraindicated in pregnancy. 

Ribavirin Interference with viral messenger RNA Lassa fever, hantavirus (hemorrhagic fever renai syndrome), hepatitis C (in chronic cases in combination with interferon a) 30-60... 

Ribavirin for Lassa fever and possibly other arenavirus infections. Supportive therapy for other VHP infections. 

Ribavirin (Tribavirin) is a synthetic nucleoside which may be administered by inhalation via a special ventilator for RSV bronchiolitis in infants and children. Efficacy for this indication is controversial, and it is usually reserved for the most severe cases, and those with co-existing illnesses, such as immunosuppression. Systemic absorption by the inhalational route is negligible. It is effective by mouth 45 h) in treating Lassa fever and, when combined with interferon alfa-2b, for chronic hepatitis C infection (see below). Systemic ribavirin is an important teratogen, and it may cause cardiac, haematological, gastrointestinal and neurological side effects. 

McCormick JB, King IJ, Webb PA, Scribner CL, Craven RB, Johnson KM, Elliott LH, Behnont-Williams R. Lassa fever. Effective therapy with ribavirin. N Engl J Med 1986 314(l) 20-6. 

Significant ribavirin side effects include anemia and hyperbilirubinemia due to mild hemolysis and a reversible block of erythropoiesis. A published study in Sierra Leone and unpublished limited trials in West Africa reported that none of the patients with anemia required transfusions. Although ribavirin is contraindicated in pregnancy, pregnant women with confirmed Lassa fever should receive ribavirin because fetal death is nearly inevitable (95%) and because evacuation of uterine contents significantly increases the pregnant patient s chances of survival (48,56). Safety of ribavirin for children and infants is not well established (48). 

Amantadine blocks the attachment, penetration, and uncoating of influenza virus A zanamivir and oseltamivir inhibit influenza viruses A and B neuraminidase, promoting viral dumping and deceasing the chance of penetration. Ribavirin becomes phosphorylated and inhibits IMP dehydrogenase and RNA polymerase. It is used to treat respiratory syncytial virus, influenza A and B, Lassa fever,... 

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. 

Clinical use and toxicity Ribavirin is used in aerosol form for respiratory syncytial virus infections. Early intravenous administration decreases mortality in Lassa fever and other viral hemorrhagic fevers. Ribavirin has recently been shown to have efficacy in treatment of hepatitis C viral infections. Aerosol ribavirin may cause conjunctival or bronchial irritation. Systemic use results in dose-dependent myelosuppression. Ribavirin is a known human teratogen. absolutely contraindicated in pregnancy. 

Ribavirin is a nonimmunosuppressive nucleoside analogue with broad antiviral properties,31 and is of proven value for some of the VHF agents. Ribavirin reduces mortality from Lassa fever in high-risk patients,32 and presumably decreases morbidity in all patients with Lassa fever, for whom current recommendations are to treat initially with ribavirin 30 mg/kg, administered intravenously, followed by 15 mg/kg every 6 hours for 4 days, and then 7.5 mg/kg every 8 hours for an additional 6 days.30 Treatment is most effective if begun within 7 days of onset lower intravenous doses or oral administration of 2 g followed by 1 g/d for 10 days also may be useful. 

Africa. Ribavirin is contraindicated in pregnant women, but, in the case of definite Lassa fever, the predictability of fetal death and the need to evacuate the uterus justify its use. Safety of ribavirin in infants and children has not been established. 

Patients receive supportive therapy, but generally speaking, there is no other treatment or established cure for VHF.s. Ribavirin, an ami-viral drug, has been effective in treating some individuals with Lassa fever or HFRS. Treatment with convalescent-phase plasma has been used with success in some patients witli Argentine hemorrhagic fever. 

Ribavirin, an antiviral drug, has been used with succc.ss in Lassa fever patients. It has been shown to be most effective when given early in the course of the illness. Patients should also receive supportive care consisting of maintenance of appropriate fluid and electrolyte balance, oxygenation and blood pressure, as well as treatment of any other complicating infections. 

Further educating people in high-risk areas about ways to decrease rodent populations in their homes will aid in the control and prevention of Lassa fever. Other challenges include developing more rapid diagnostic tests and increasing the availability of the only known drug treatment, ribavirin. Research is presently under way to develop a vaccine for Lassa fever. 

Viral A hemor hagic fevers (Ebola, Marburg, Lassa) Animals— rodents, ticks 4-21 days Yes Contact Fever, massive hemor hage, malaise, facial/ ho ax fl ushing, HA, V/D, hypotension Fatal w/in 2 weeks Supportive, fluid replacement ribavirin for Congo-Crimean HF/arenavi ruses... 

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