Uses
What is Relenza used for?
Relenza (zanamivir) is commonly used for the treatment of the flu (influenza A and B), but only within the first two days of having flu symptoms. Relenza is also used for the prevention of flu. The flu, short for influenza, is caused by influenza viruses that infect parts of the body, leading to symptoms such as fever, cough, sore throat, body aches, and fatigue.
Relenza may also be used for other conditions as determined by your healthcare provider.
How does Relenza work (mechanism of action)?
Relenza blocks the creation of new flu virus particles, which helps your body’s immune system fight the infection.
How is Relenza supplied (dosage forms)?
Brands and other names
- Relenza
Dosage forms and strengths
- 5 mg per blister inhalation powder for use with the Diskhaler device
How should I store Relenza?
Relenza inhalation powder blister pack and inhalation device should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Do not puncture the blister packs unless taking a dose using the inhalation device.
Side Effects
What are the most common side effects of Relenza?
The most common side effects of Relenza are listed below. Tell your healthcare provider if you have any of these side effects that bother you.
- Sinus infection
- Dizziness
- Fever and chills
- Joint or muscle pain
There may be other side effects of Relenza that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of Relenza?
While less common, the most serious side effects of Relenza are described below, along with what to do if they happen.
Sudden Breathing Problems. Relenza may cause the muscles around your airways to tighten (bronchospasm) right after you use it. In some cases, this can be serious. Stop using Relenza and contact your healthcare provider right away if you develop any of the following symptoms.
- Worsening breathing
- Shortness of breath
- Chest pain or tightness
- Cough
Hallucinations or Psychotic-like Behaviors. Relenza may cause hallucinations or psychotic-like behaviors. Tell your healthcare provider right away if you have any of the following symptoms, or if you have been told by others you have these symptoms.
- Hearing, seeing, smelling, tasting, or otherwise perceiving things that others do not
- Delusional thoughts, such as false beliefs that you are being controlled
- Disorganized thoughts, such as jumping between topics or having a hard time focusing
- Sudden decline in self-care, such as personal hygiene or academic/work performance
- Aggressive behavior
Severe Allergic Reactions. Relenza may cause allergic reactions, which can be serious. Stop using Relenza and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching, skin rash, or pale red bumps on the skin called hives
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
Warnings & Precautions
Who should not use Relenza?
Allergies to Ingredients. People who are allergic to any of the following should not use Relenza.
- Relenza
- Zanamivir
- Milk proteins
- Any of the ingredients in the specific product dispensed
Your pharmacist can tell you all of the ingredients in Relenza.
What should I know about Relenza before using it?
Do not use Relenza unless it has been prescribed to you by a healthcare provider. Use it as prescribed.
Do not share Relenza with other people, even if they have the same condition as you. It may harm them.
This medicine is inhaled by mouth. Make sure you understand how to properly use the inhalation device and inhale the medicine. Talk to your healthcare provider if you have any questions.
If you use an inhaled bronchodilator, like albuterol, and are due for a dose at the same time as Relenza, use the inhaled bronchodilator first.
Relenza can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how Relenza affects you.
Relenza only works against the flu virus. Talk to your healthcare provider if your symptoms get worse or do not improve. This may be a sign of another type of infection.
Keep Relenza out of the reach of children.
What should I tell my healthcare provider before using Relenza?
Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if Relenza is right for you.
In particular, make sure that you discuss any of the following.
Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.
- Breathing problems, including asthma or chronic obstructive pulmonary disease (COPD)
- History of mental health problems, including hallucinations
- Kidney problems
Vaccines. Talk with your healthcare provider about any vaccines that you may need. You should not receive certain vaccines right before or while using Relenza. Tell your healthcare provider about any vaccines you have recently received or have scheduled.
Other Medicines and Supplements. Relenza may interact with other medicines and supplements. Before using Relenza, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.
Pregnancy. It is not known if or how Relenza could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant.
Breastfeeding. It is not known if Relenza passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should take Relenza while breastfeeding.
How can I get more information about Relenza?
For more information about Relenza, you can visit the manufacturer’s website at www.gsk.com.
Interactions
Does Relenza interact with foods or drinks?
There are no known interactions between Relenza and foods or drinks.
It is unknown if drinking alcohol will affect Relenza, but heavy drinking can slow your immune response and make it harder for your body to fight infection.
Does Relenza interact with other medicines (drug interactions)?
Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
In particular, make sure that you discuss if you have recently received or plan to receive a live flu vaccine.
This may not be a complete list of medicines that can interact with Relenza. Always check with your healthcare provider.
Overdose/Missed Dose
What should I do if I accidentally use too much Relenza?
If you or someone else has used too much Relenza, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
What should I do if I miss a dose of Relenza?
If you miss a dose, take it as soon as you remember. If it is two hours or less until your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.
Are you currently using Relenza (zanamivir)?
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