Oseltamivir and zanamivir are new antivirals that
selectively inhibit the neuraminidaseof influenza A and B viruses. The
neuraminidase cleaves terminal sialic acid from glyco-conjugates and plays a
role in the release of virus from infected cells. Zanamivir was the first
approved neuraminidase inhibitor. It is given by oral inhalation using a
specially de-signed device. Oseltamivir phosphate is the oral prodrug of
oseltamivir, a drug compara-ble to zanamivir in antineuraminidase activity.
Treatment with either oseltamivir and zanamivir
reduces influenza symptoms and shortens the course of illness by 1 to 1.5 days.
The activity of these compounds against both influenza A and B offers an
advantage over amantadine and rimantadine, which are active only against