Relenza (generic: zanamivir) is a prescription medication used to treat and prevent influenza ("flu") in adults and children.  Relenza belongs to a group of drugs called neuraminidase inhibitors, which stop the growth and spread of the flu virus in the body.

This medication comes in powder form to be inhaled by mouth. In people with the flu, Relenza is inhaled twice daily for 5 days. For prevention of the flu, it is inhaled once daily for 10 to 28 days.

Some of the common side effects of Relenza include headache, diarrhea, and nausea.