Cold & Flu Treatment How to Use Relenza to Treat the Flu By Kristina Duda, RN facebook twitter linkedin Kristina Duda, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention. Learn about our editorial process Kristina Duda, RN Medically reviewed by Medically reviewed by Jason DelCollo, DO on November 30, 2019 Jason DelCollo, DO, board-certified in family medicine. He is associate faculty at Philadelphia College of Osteopathic Medicine as well as adjunct faculty with the Crozer Family Medicine Residency Program, and is an attending physician at Glen Mills Family Medicine in Glen Mills, Pennsylvania. Learn about our Medical Review Board Jason DelCollo, DO Updated on January 22, 2020 Print Table of Contents View All Table of Contents Who Can Use Relenza Who Shouldn't Use Relenza Side Effects How to Use Relenza Is It Better Than a Flu Shot? Choosing Antiviral Treatment There are several options for antiviral treatments if you have the flu. The most commonly prescribed is Tamiflu, but another option is a medication called Relenza (zanamivir). This antiviral flu medicine is inhaled through the mouth, similar to an inhaler that is used for asthma. Westend61/Getty Images Who Can Use Relenza Relenza is approved for use by adults and children over 7 years old. It can be used to treat the flu if you start taking it within 48 hours of the start of your symptoms. It can also be used to prevent the flu if you are in close contact with someone who has it. If it is being used for flu prevention, it can be used by children as young as five. Dosing differs depending on what you are using Relenza for. If you are taking it to treat your flu symptoms, the recommended dosing is to take it twice a day (about 12 hours apart) for 5 days. If you are taking it to prevent influenza and someone in your home is already sick with it, Relenza is usually taken once a day for 10 days. Some people who are at high risk for complications from the flu may take antiviral medications to prevent the flu when there is an outbreak in the community. In those cases, it may be recommended that you take Relenza once a day for 28 days. It's important to take the medicine at about the same time every day. This allows a consistent amount of medication to remain in your body, increasing its effectiveness. Who Shouldn't Use Relenza It is not approved for use by children under the age of 7. Because Relenza is an inhaled medicine, people with asthma or chronic lung diseases should not use it. It also should not be used by those who have lactose (a sugar in milk and dairy products) allergy because the medicine contains lactose. If you are pregnant or nursing, talk to your doctor about the pros and cons of taking Relenza. The flu can be very serious or even life-threatening for women who are pregnant. Your health care provider can help you decide which treatment is right for you. Side Effects Every medication causes side effects in some people. The most commonly occurring side effects in those taking Relenza include: DiarrheaNauseaVomitingHeadacheDizzinessNasal irritationCoughEar, nose or throat infections If you or your child is taking Relenza and you experience one of these side effects, don't panic. Most of the time, these side effects will be mild and may not even be noticeable as many are symptoms of the flu as well. If you notice a significant difference in your symptoms after you start taking the medicine that concern you, contact your healthcare provider. Occasionally, people may experience more serious adverse effects while taking Relenza. These may include: Difficulty breathing - Most often in those with lung diseases such as asthma.Seizures, confusion or abnormal behavior - These have occurred in children and teenagers being treated for the flu and those who have the flu but are not taking any antiviral medicines. Injury or death can occur due to these conditions. If you see these occur, contact a health care provider or seek medical attention right away.Allergic reaction - Severe allergic reaction can occur when taking this medicine. If you experience dizziness, difficulty breathing, swelling of the mouth or tongue, hives, difficulty swallowing, hoarseness, wheezing, or shortness of breath, seek medical attention immediately. If you are allergic to components of the medication, you should not take Relenza. It's important to know that these serious adverse events are very rare. It's important to know what to watch for, but the chances that you or someone you know will experience any of these is extremely low. How to Use Relenza If you are prescribed Relenza, your health care provider or pharmacist should demonstrate how to take it. The medicine is administered through a device called a diskhaler. There are blister packs inside the diskhaler that have a powdered medicine in them that is inhaled through the mouth. How often you use it depends on whether you are taking Relenza to treat or prevent the flu. You should not take Relenza if you have not been instructed how to use it or don't understand the instructions. Is It Better Than a Flu Shot? Antiviral medicines, including Relenza, are not a substitute for flu vaccines. The flu vaccine is the best way to prevent the flu. However, some people may not be able to get flu vaccines due to allergies or other medical concerns. If you are not able to get vaccinated and you are at high risk for complications from the flu, using an antiviral medicine may be an option to keep you from getting sick. It's also important to use basic infection prevention techniques, like washing your hands frequently, avoiding those who are sick, and using hand sanitizer when soap and water aren't available. How to Choose Which Antiviral Treatment Is Best All antiviral flu medicines are available by prescription only. Talk to your health care provider about your options and together, you can decide which one is right for you. If you can start taking it within the first 48 hours of the onset of your flu symptoms, it is more likely to help you feel better faster. Was this page helpful? Thanks for your feedback! Looking to avoid getting the flu? Our free guide has everything you need to stay healthy this season. Sign up and get yours today. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Zanamivir Oral Inhalation: MedlinePlus Drug Information. Prevention and Control of Seasonal Influenza With Vaccines. Health Professionals. Seasonal Influenza (Flu). Research C for DE and. Postmarket Drug Safety Information for Patients and Providers - Relenza: Consumer Questions and Answers.