Relenza (zanamivir) is an antiviral medication. It blocks the actions of viruses in your body.
Relenza is used to treat flu symptoms caused by influenza virus in patients who have had symptoms for less than 2 days. Relenza may also be given to prevent influenza in people who may be exposed but do not yet have symptoms. Zanamivir will not treat the common cold.
Relenza should not be used in place of getting a yearly flu shot. The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.
Important information
Relenza should not be used in place of getting a yearly flu shot. The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.
Before using Relenza, tell your doctor if you have asthma, chronic obstructive pulmonary disease (COPD), or any other chronic lung condition. Serious or life-threatening bronchospasm (difficulty breathing) and other effects on the lungs can occur while using Relenza. Stop using this medicine and call your doctor at once if you have wheezing or severe breathing problems. Do not use a nebulizer or ventilator to give this medicine. Relenza inhalation powder should never be mixed with a liquid.
Treatment with Relenza should start as soon as possible when flu symptoms appear, such as fever, chills, muscle aches, sore throat, and runny or stuffy nose.
Do not use Relenza to treat flu symptoms in a child younger than 7 years old. Children as young as 5 years old may use the medication to prevent flu symptoms. Do not use an inhaled nasal flu vaccine (FluMist) within 2 weeks before or 48 hours after using Relenza. Zanamivir may interfere with the drug action of FluMist, making the vaccine less effective. Follow your doctor"s instructions.
Some people using zanamivir have had rare side effects of confusion, delirium and self-injury. These symptoms have occurred most often in children. It is not known whether this medicine was the exact cause of these symptoms. However, anyone using Relenza should be watched closely for signs of confusion or unusual behavior. Call a doctor at once if you or the child using this medicine has any of these symptoms.
Before using Relenza
You should not use Relenza if you are allergic to zanamivir or to lactose (milk protein). Before using this medicine, tell your doctor if you have asthma, chronic obstructive pulmonary disease (COPD), or any other chronic lung condition. Serious or life-threatening bronchospasm (difficulty breathing) and other effects on the lungs can occur while using Relenza.
If you have asthma, COPD, or other chronic lung disease, make sure you have a fast-acting inhaled bronchodilator available to treat any serious breathing problems that may occur while using Relenza. Fast-acting bronchodilators include albuterol (Ventolin, Proventil), bitolterol (Tornalate), metaproterenol (Alupent), and pirbuterol (Maxair). Talk with your doctor about which medicine is best for you.
If you are scheduled to use a bronchodilator at the same time as Relenza, use the bronchodilator first.
FDA pregnancy category C. It is not known whether Relenza will harm an unborn baby. Tell your doctor if you are pregnant. Your doctor will decide whether you should receive Relenza, especially if you have a high risk of infection with influenza. It is not known whether zanamivir passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.
See also: Pregnancy and breastfeeding warnings (in more detail)
Do not use this medication to treat flu symptoms in a child younger than 7 years old. Children as young as 5 years old may use the medication to prevent flu symptoms.
How should I use Relenza?
Use Relenza exactly as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.
Treatment with Relenza should start as soon as possible when flu symptoms appear, such as fever, chills, muscle aches, sore throat, and runny or stuffy nose.
Relenza is packaged in disk-shaped foil packs that contain 4 blisters of medicine. These disks are placed into a device called a DISKHALER that you will use to inhale the medicine. The device opens and loads a blister of inhalation powder each time you use the inhaler. The disk device is not to be used with a spacer. Follow the patient instructions provided with the DISKHALER.
Do not use a nebulizer or ventilator to give Relenza. Zanamivir inhalation powder should never be mixed with a liquid. Do not use any other medicines in the DISKHALER. Always put the cover back on the device when not in use.
To treat flu symptoms: Use 2 inhalations every 12 hours for 5 days. Your doctor may tell you to use two doses on the first day of treatment, spaced at least 2 hours apart. On the following days, the doses should be spaced 12 hours apart. Follow your doctor"s instructions.
To prevent flu symptoms: Use 2 inhalations every 24 hours for 10 to 28 days. Follow your doctor"s instructions.
If you have a chronic respiratory disease such as asthma or COPD and you are scheduled to use an inhaled bronchodilator at the same time as Relenza, use the inhaled bronchodilator before using this medicine.
Use this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Tell your doctor if your symptoms do not improve, or if they get worse.
Store Relenza at room temperature away from moisture and heat. Throw away the DISKHALER after your treatment ends.
What happens if I miss a dose?
Use the missed dose as soon as you remember. Skip the missed dose if it is within 2 hours of your next scheduled dose. Do not use extra medicine to make up the missed dose.
Call your doctor if you miss several doses.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid?
Do not use an inhaled nasal flu vaccine (FluMist) within 2 weeks before or 48 hours after using Relenza. Zanamivir may interfere with the drug action of FluMist, making the vaccine less effective. Follow your doctor"s instructions.
Relenza side effects
Get emergency medical help if you have any of these signs of an allergic reaction to Relenza: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Some people using zanamivir have had rare side effects of confusion, delirium and self-injury. These symptoms have occurred most often in children. It is not known whether Relenza was the exact cause of these symptoms. However, anyone using this medicine should be watched closely for signs of confusion or unusual behavior. Call a doctor at once if you or the child using Relenza has any of these symptoms.
Stop using Relenza and call your doctor at once if you have wheezing or severe breathing problems, or if you feel like you might pass out.
Less serious Relenza side effects may include:
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headache;
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dizziness;
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nausea, vomiting, diarrhea;
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fever, chills, joint pain;
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ear pain; or
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cold symptoms such as stuffy nose, sneezing, sore throat;
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect Relenza?
There may be other drugs that can interact with Relenza. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.
