Influenza virus neuraminidase inhibitors

Neuraminidase promotes influenza virus release from infected cells and faci litates virus spread within the respiratory tract. Several potent and speci fic inhibitors of this enzyme have been developed, and two (zanamivir and o seltamivir) have been approved for human use. Unlike amantadine and rimanta dine that target the M2 protein of influenza A viruses, these drugs inhibit replication of both influenza A and B viruses. Zanamivir is delivered by i nhalation because of its low oral bioavailability whereas oseltamivir is ad ministered by mouth. Early treatment with either drug reduces the severity and duration of influenza symptoms and associated complications. Both agent s are effective for chemoprophylaxis. Because of a broader antiviral spectr um, better tolerance, and less potential for emergence of resistance than i s seen with the M2 inhibitors, the neuraminidase inhibitors represent an im portant advance in the treatment of influenza.