Effectiveness and role of zanamivir in the treatment of influenza infection

Influenza is a worldwide public health issue. The virus circulates annually in winter and can cause significant morbidity in time general population a nd increased mortality rates in those who are more susceptible to complicat ions if infected by the virus, especially the elderly. Although antivirals to treat and prevent influenza have been available in several countries for up to 30 years, annual influenza vaccination strategies remain the primary focus in reducing the burden of illness caused by this viral infection. Za namivir is the first of a new class of compounds to offer significant advan tages over existing influenza treatments. It is a potent and specific compe titive inhibitor of both influenza A and B virus neuraminidase. The drug is administered topically by inhalation directly to the site of virus replica tion in a dose of 10 mg twice daily for 5 days. In both experimental and na turally acquired treatment studies, zanamivir has been shown to have effica cy against both influenza A and B virus and to be well tolerated. Significa nt treatment benefits resulting in reductions in illness of up to 2.5 days have been demonstrated in both the general population and in patients consi dered at high risk. In addition, patients receiving zanamivir have been abl e to return to normal activities significantly faster.