Published: January 2000

Influenza Infection, Relenza (zanamivir) and Adverse Respiratory Events

January 2000

Glaxo Wellcome New Zealand Ltd has advised Medsafe that the following information will be sent to New Zealand doctors and pharmacists prior to the 2000 flu season:

With influenza circulating widely throughout Europe and the USA, Glaxo Wellcome wish to remind prescribers prior to the influenza season commencing in NZ of the wider aspects of influenza management and also highlight important new safety information concerning Relenza (zanamivir).


Vaccination remains the cornerstone of influenza management and provides significant protection against strains of influenza virus included in the vaccine. [Medsafe: Relenza is currently not indicated for prophylaxis against influenza]

Bacterial Infection

Patients presenting with symptoms consistent with influenza may have bacterial infections. It is important to consider this as a possible diagnosis, and recognise that bacterial infections may co-exist with influenza infection. Appropriate antibacterial treatment should be initiated whenever bacterial infection is suspected, irrespective of the use of specific anti-influenza treatment such as Relenza.

Respiratory Adverse Events In Patients Using Relenza

Relenza is a new, inhaled treatment for influenza A and B infection. Since the beginning of the influenza season in Europe and North America this year, in excess of 500,000 prescriptions for Relenza have been dispensed. Adverse events, including bronchospasm and/or decline in respiratory function, some of which have been serious, have been reported in association with the use of Relenza during the Northern Hemishpere influenza season. These events have been reported rarely in patients with underlying respiratory disease (asthma, chronic obstructive pulmonary disease (COPD)) and have also been reported very rarely in patients without underlying respiratory disease.

Influenza can be a serious illness, particularly in patients with underlying respiratory conditions such as asthma and COPD and airways hyperreactivity can be associated with influenza. Determining the causality of these adverse events is difficult given the nature of influenza, the presence of underlying diseases and the use of concomitant medications in many of the cases reported.

Patients who experience adverse events such as bronchospasm or decline in respiratory function should stop using Relenza and seek medical advice immediately.

Patients with asthma and COPD should be informed of the potential risk of bronchospasm when using Relenza and advised to ensure that a fast-acting bronchodilator is available. Patients on maintenance bronchodilator therapy should be advised to use their bronchodilators before taking Relenza.

Changes have been made to the Data Sheet for Relenza to reflect this new information. Prescribers are reminded of the importance of providing appropriate information, as contained in the revised Data Sheet, to patients when prescribing Relenza.

Please contact Glaxo Wellcome New Zealand Limited on 0800 808 500 if you have any questions regarding Relenza.