Rather than just covering up the symptoms, Relenza is a medicine used to treat influenza at its source. Relenza attacks the flu virus and prevents it from spreading inside your body.
Who can take Relenza?
If flu symptoms have appeared within the last day or two, you or anyone in your family above 7 years of age may consider taking Relenza. If you’re not sure whether you’re dealing with a cold or influenza, read more about how to tell the difference and what to do.
Common symptoms of the flu include sudden onset of fever, headache, fatigue, cough, body aches, and sore throat. Always talk to your doctor to find out if the medication is right for you or your family members.
Who should not take Relenza?
People with asthma and other lung diseases should not take Relenza, as they may be at a higher risk of developing a dangerous breathing problem called bronchospasm. If you’re managing asthma symptoms with maintenance medication, you may also want to review asthma relief with Advair.
You should not take Relenza if you are allergic to zanamivir or any other ingredient found in the medication. Also, make your doctor aware if you have any type of chronic condition, including lung or heart disease, if you are allergic to any other medicines or food products, or if you are pregnant.
How fast does Relenza work?
For adults and children with the flu who take Relenza, recovery time is approximately one day faster on average than for those who choose not to take it. For comparison, you can also read about flu prevention and treatment with Tamiflu.
How should Relenza be stored?
Relenza should be kept at room temperature below 77 degrees Fahrenheit (25 degrees Celsius). Keep Relenza out of reach of children as it is not in a childproof container.
What are some common side effects?
The most common side effects in adults and adolescents have been:
- headaches
- nausea
- diarrhea
- vomiting
- nasal irritation
- bronchitis
- cough
- ear, nose, and throat infections
- dizziness
For children, side effects can be:
- ear, nose, and throat infections
- vomiting
- diarrhea
If side effects persist or worsen while taking Relenza, please be sure to contact your doctor. If you’re looking for additional symptom relief options, see our guide to over-the-counter drugs used to fight colds and flu.

