Neuraminidase inhibitors are recommended for use against influenza and its complications in interpandemic years and in a pandemic.
Researchers assessed the effects of neuraminidase inhibitors in preventing or ameliorating influenza, its transmission and its complications in healthy adults and to estimate the frequency of adverse effects.
They identified 4 prophylaxis, 13 treatment and 4 post-exposure prophylaxis trials.
In prophylaxis compared to placebo, neuraminidase inhibitors have no effect against influenza-like illnesses ( relative risk, RR 1.28, for oral Oseltamivir 75 mg daily; RR 1.51, for inhaled Zanamivir 10 mg daily ).
The efficacy of oral Oseltamivir ( Tamiflu ) 75 mg daily against symptomatic influenza is 61% ( RR 0.39 ), or 73% ( RR 0.27 ) at 150 mg daily.
Inhaled Zanamivir ( Relenza ) 10 mg daily is 62% efficacious ( RR 0.38 ).
Neither neuraminidase inhibitor has a significant effect on asymptomatic influenza.
Oseltamivir for post-exposure prophylaxis has an efficacy of 58.5% ( 15.6% to 79.6 ) for households and of 68% ( 34.9 to 84.2% ) to 89% in contacts of index cases.
Zanamivir has similar performance.
The hazard ratios for time to alleviation of influenza symptoms were in favour of the treated group 1.33 for Zanamivir and 1.30 for Oseltamivir.
Oseltamivir 150 mg daily prevented lower respiratory tract complications ( OR 0.32 ).
Because of their low effectiveness, neuraminidase inhibitors should not be used in routine seasonal influenza control.
Source: Cochrane Database of Systematic Reviews, 2006