Neuraminidase Inhibitors for Influenza

Neuraminidase inhibitors are a class of medications used in the management of influenza A and B infection. Neuraminidase is an enzyme found on the surface of the influenza virus that is important for the movement of virus particles into target cells and the subsequent release of new virus particles from infected cells. Blocking this enzyme, therefore, inhibits viral replication within the body.

There are currently three neuraminidase inhibitors registered in Australia: oseltamivir, zanamivir, and peramivir. Peramivir is a newer agent that is administered as a single intravenous infusion. It is indicated for the treatment of acute influenza in adults and children from two years of age within 48 hours of symptom onset.

A large double-blind, double-dummy randomised controlled study compared the safety and efficacy of peramivir and oseltamivir. Subjects with confirmed influenza A or B were randomly assigned to receive a single infusion of peramivir (300mg or 600mg) or a five-day course of oseltamivir. This study concluded that peramivir is non-inferior to oseltamivir for the primary endpoint of time to alleviation of symptoms. In regards to safety, the overall incidence of adverse reactions was lower in the peramivir groups, although the rate of severe adverse reactions was similar across all groups. Surveillance data may be consulted for current information on local epidemiology and resistance profile of the circulating influenza strain.

A brief overview of the different neuraminidase inhibitors is shown in Table 1.