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.
Relenza is a prescription medicine for the treatment of influenza (flu, infection caused by influenza virus) and for reducing the chance of getting the flu in community and household settings. Relenza is for adults and children at least 7 years of age who have flu symptoms that appeared within the previous day or two. Typical symptoms of the flu include:
- sudden onset of fever
- muscular weakness
- sore throat
Relenza can also help reduce the chance of getting the flu in adults and children at least 5 years of age who have a higher chance of getting the flu because they spend time with someone who has the flu. Relenza can also reduce the chance of getting the flu if there is a flu outbreak in the community.
This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.
Some patients have had breathing problems while taking Relenza. This can be very serious and need treatment right away. Most of the patients who had this problem had asthma or chronic obstructive pulmonary disease, but some did not. If you have trouble breathing or have wheezing after your dose of Relenza, stop taking Relenza and get medical attention.
In studies, the most common side effects with Relenza have been:
- nasal irritation;
- ear, nose, and throat infections;
- and dizziness.
Other side effects that have been reported, but were not as common, include rashes and allergic reactions, some of which were severe.
People with influenza (the flu), particularly children and adolescents, may be at an increased risk of seizures, confusion, or abnormal behavior early in their illness. These events may occur after beginning Relenza or may occur when flu is not treated. These events are uncommon but may result in accidental injury to the patient. Therefore, patients should be observed for signs of unusual behavior and a healthcare professional should be contacted immediately if the patient shows any signs of unusual behavior.
If you are not feeling well when you take Relenza, you may faint or become lightheaded after inhaling Relenza. You should sit down in a relaxed position before inhaling the dose of Relenza, and you should only hold your breath for as long as is comfortable after inhaling the dose.
If you are not feeling well, you are advised to have someone with you while you are inhaling the dose of Relenza.
This list of side effects is not complete. Your healthcare provider or pharmacist can discuss with you a more complete list of possible side effects with Relenza. Talk to your healthcare provider promptly about any side effects you have.
Tell your healthcare provider about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.
Let your healthcare provider know if you received live attenuated influenza vaccine (Flumist) intranasal in the past 2 weeks.
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 recommended for people with chronic respiratory disease such as asthma or chronic obstructive pulmonary disease.
If you develop worsening respiratory symptoms such as wheezing or shortness of breath, stop using Relenza and contact your healthcare provider right away.
If you have chronic respiratory disease such as asthma and chronic obstructive pulmonary disease and your healthcare provider has prescribed Relenza, you should have a fast-acting, inhaled bronchodilator available for your use. If you are scheduled to use an inhaled bronchodilator at the same time as Relenza, use the inhaled bronchodilator before using Relenza.
You should not take Relenza if you are allergic to zanamivir or any other ingredient of Relenza. Also tell your healthcare provider if you have any type of chronic condition including lung or heart disease, if you are allergic to any other medicines, milk proteins or other food products, or if you are pregnant.
Relenza was not effective in reducing the chance of getting the flu in 2 studies in nursing home patients.
Relenza does not treat flu-like illness that is not caused by influenza virus.
Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of Relenza there are no specific foods that you must exclude from your diet when receiving Relenza.
Tell your doctor if you are allergic to Relenza or any other medicines.
Tell your doctor if you:
- are pregnant or breastfeeding.
- have asthma or other breathing problems
- have heart, kidney, or liver disease
Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.
If you are pregnant or planning to become pregnant while taking Relenza, talk to your healthcare provider before taking this medication. Relenza is normally not recommended for use during pregnancy, as the effects on the unborn child are unknown.
Tell your healthcare provider if you are breastfeeding or plan to breastfeed. It is not known if Relenza excreted in human breast milk or if it will harm your nursing baby.
Relenza is packaged in medicine disks called ROTADISKS® and is inhaled by mouth using a delivery device called a DISKHALER®. Each ROTADISK contains 4 blisters. Each blister contains 5 mg of active drug and 20 mg of lactose powder (which contains milk proteins).
You should receive a demonstration on how to use Relenza in the DISKHALER from a healthcare provider. Before taking Relenza, read the “Patient Instructions for Use.” Make sure that you understand these instructions and talk to your healthcare provider if you have any questions. Children who use Relenza should always be supervised by an adult who understands how to use Relenza. Proper use of the DISKHALER to inhale the drug is necessary for safe and effective use of Relenza.
If you have the flu the usual dose for treatment is 2 inhalations of Relenza (1 blister per inhalation) twice daily (in the morning and evening) for 5 days. It is important that you begin your treatment with Relenza as soon as possible from the first appearance of your flu symptoms. Take 2 doses on the first day of treatment whenever possible if there are at least 2 hours between doses.
To reduce the chance of getting the flu, the usual dose is 2 inhalations of Relenza (1 blister per inhalation) once daily for 10 or 28 days as prescribed by your healthcare provider.
Never share Relenza with anyone, even if they have the same symptoms. If you feel worse or develop new symptoms during treatment with Relenza, or if your flu symptoms do not start to get better, stop using the medicine and contact your healthcare provider.
If you forget to take your medicine at any time, take the missed dose as soon as you remember, except if it is near the next dose (within 2 hours). Then continue to take Relenza at the usual times. You do not need to take a double dose. If you have missed several doses, inform your healthcare provider and follow the advice given to you.
Treatment of Influenza
- The recommended dose of Relenza for treatment of influenza in adults and children aged 7 years and older is 10 mg twice daily (approximately 12 hours apart) for 5 days.
- Two doses should be taken on the first day of treatment whenever possible provided there is at least 2 hours between doses.
- On subsequent days, doses should be about 12 hours apart (e.g., morning and evening) at approximately the same time each day.
- The safety and efficacy of repeated treatment courses have not been studied.
If you take too much Relenza, call your local Poison Control Center or seek emergency medical attention right away.
Active ingredient: zanamivir
Inactive ingredient: lactose
Relenza should be stored at room temperature below 77°F (25°C). Relenza is not in a childproof container. Keep Relenza out of the reach of children. Discard the DISKHALER after finishing your treatment.