Last reviewed 01/2018

Zanamivir is a specific inhibitor of influenza virus neuraminidase. Zanamivir is licensed for the treatment of influenza A and B.

In clinical trials Zanamivir:

  • has been shown to reduce the duration of major symptoms in a population of previously healthy patients who presented with symptoms of influenza during a documented epidemic
  • reduces duration of symptoms by 1 to 1.5 days
  • patients who presented early after the onset of influenza symptoms with a fever >= 37.8 degrees C or who were at high risk of complications had the most benefit (2)

Note that when influenza is active in a community 60-80% of patients with flu-like symptoms will have influenza. If there is not a influenza outbreak the accuracy of clinical

The summary of product characteristics should be consulted before prescribing this drug.

Zanamivir may be prescribed to at risk individuals when influenza is circulating in the community.


  • (1) Drug and Therapeutics Bulletin (1999). "Zanamivir for influenza". 37(11), 81-4.
  • (2) Monto AS, Flemming DM, Henry D et al (1999). Efficacy and safety of the neuraminidase inhibitor zanamivir in the treatment of influenza A and B virus infections. J Infect Dis, 180, 254-61.