[Neuraminidase inhibitor].

Amantadine, effective to influenza A virus, is now widely used in Japan. Recently new anti-influenzal agents, neuramidase inhibitor has been developed. Both Zanamivir (inhaled type) and Oseltamivir(oral use), are proved to be effective in treatment of influenza A and B. Mechanism of action on influenza virus, dosage, side effects of the anti-influenza agents are described. Clinicians expect to medicate to influenza with the agents as soon as possible.