Relenza (zanamivir)

FDA has approved Relenza (zanamivir), an anti-viral drug, for persons aged 7 years and older for the treatment of uncomplicated influenza virus. This product is approved to treat type A and B influenza, the two types most responsible for flu epidemics. Clinical studies showed that for the drug to be effective, patients needed to start treatment within two days of the onset of symptoms. The drug seemed to be less effective in patients whose symptoms weren't severe or didn't include a fever.

Relenza is a powder that is inhaled twice a day for five days from a breath-activated plastic device called a Diskhaler. Patients should get instruction from a health-care practitioner in the proper use of the Diskhaler, including a demonstration when possible.  Relenza has not been shown to be effective, and may carry risk, in patients with severe asthma or a lung condition called chronic obstructive pulmonary disease. Some patients with mild or moderate asthma experienced bronchospasm (marked by shortness of breath) after using Relenza.

Some patients have had bronchospasm (wheezing) or serious breathing problems when they used Relenza. Many but not all of these patients had previous asthma or chronic obstructive pulmonary disease. Relenza has not been shown to shorten the duration of influenza in people with these diseases. Because of the risk of side effects and because it has not been shown to help them, Relenza is not generally recommended for people with chronic respiratory disease. Anyone who develops bronchospasm worsening respiratory symptoms such as wheezing and shortness of breath should stop taking the drug and call their health-care provider. Patients with underlying respiratory disease should have a fast-acting inhaled bronchodilator available when taking Relenza.

• Relenza Approval, Review and Labeling Information (from Drugs@FDA)
• Letter from the Glaxo Wellcome, Inc. on Relenza (zanamivir for inhalation). July 2000  Optional format:  PDF.  This letter notifies health professionals of important revisions to the safety labeling for Relenza.
• Consumer Drug Information Sheet
• Transcript of the Antiviral Advisory Committee Date:  2/24/99; Topic: Relenza (zanamivir); NDA 21-036.   Optional format: PDF.  Also available:  Minutes PDF.
• Combined Memorandum. (Issued, 7/15/99, Posted, 8/27/99)  This memo addresses several concerns raised by the Antiviral Drug Advisory Committee held on February 24, 1999.
• Division Director Memorandum. (Issued, 7/26/99, Posted, 8/27/99)  This memo states the Director's rationale for recommending approval of Relenza for treatment of uncomplicated influenza, plus comments on other noteworthy aspects of the application.

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Date created: October 13, 2004

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