Relenza (zanamivir) is a brand-name drug that’s prescribed for the flu in adults and some children. Relenza comes as a powder that you inhale once or twice per day. The dosage can vary depending on certain factors.
Relenza is approved by the Food and Drug Administration (FDA) to treat infections caused by the influenza A and B viruses (the flu). It’s used in adults and children ages 7 years and older who have had flu symptoms for 2 days or less. Relenza is also approved to help prevent the flu in adults and children ages 5 years and older.
Relenza belongs to a drug class called antivirals. It’s not available in a generic version.
Keep reading for specific information about the dosage of Relenza, including its strength and how to use the medication. For a comprehensive look at Relenza, see this article.
Note: This article describes typical dosages for Relenza provided by the drug’s manufacturer. When using Relenza, always follow the dosage prescribed by your doctor.
The information below describes Relenza’s typical dosages and other details about the drug.
Relenza form
Relenza comes as a powder in a blister pack that you breathe in through your mouth using an inhaler.
Relenza strength
Relenza comes in one strength of 5 milligrams (mg).
Typical dosages
The following information describes dosages that are commonly prescribed or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.
Dosage to treat the flu
Doctors may prescribe Relenza to treat the flu. The recommended dose for this use is 10 mg (two 5-mg inhalations). Typically, you’ll take this dose twice daily for 5 days.
For more information about your specific dosage, talk with your doctor.
Dosage to prevent the flu
Relenza is also approved to help prevent the flu. The recommended dose for this use is 10 mg (two 5-mg inhalations). For this use, you’ll use Relenza once daily for 10 or 28 days.
Talk with your doctor if you have questions about your dosage.
Children’s dosage
Relenza is approved to treat the flu in children ages 7 years and older. It’s also approved to help prevent the flu in children ages 5 years and older.
The dosages to treat or prevent the flu are the same as the dosages for adults. See the “Typical dosages” section just above for details.
Talk with your child’s doctor if you have questions about their dosage.
How to use Relenza
Relenza comes as a powder in a disk-shaped blister pack. You’ll breathe it in through your mouth using an inhaler. You’ll inhale it once or twice per day.
If you’re using Relenza to treat the flu, your doctor may recommend taking two doses separated by at least 2 hours on the first day of treatment. Typically, you’ll use Relenza every 12 hours (twice per day). This helps maintain a steady level of the drug in your body so Relenza can work effectively.
If you’re using Relenza to help prevent the flu, you’ll use it once per day at the same time each day.
If you have questions about how to use Relenza, talk with your doctor or pharmacist. There are also step-by-step instructions in the drug’s prescribing information.
Long-term treatment
Relenza is used short term to treat or help prevent the flu. Doctors prescribe Relenza for 5 days to treat the flu and for 10 or 28 days at a time to help prevent the flu.
Talk with your doctor if you have questions about how long you can expect to use Relenza.
ACCESSIBLE DRUG LABELSSome pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.
Below are some frequently asked questions about Relenza.
Is the dosage of Relenza similar to the dosage of Tamiflu?
No. Both Relenza and Tamiflu are used to treat and help prevent the flu, but the forms and dosages of the drugs are different.
Relenza comes as a powder that you breathe in through your mouth. Tamiflu comes as an oral capsule or a powder for liquid suspension (a type of liquid mixture) that you swallow. The dosages are also different for each drug because they have different active ingredients. Your doctor will prescribe the drug and the dosage that’s right for you.
To learn more about how the dosages of Relenza and Tamiflu compare, talk with your doctor.
How long does it take for Relenza to start working?
Relenza starts to work after your first dose. Your flu symptoms should ease a few days after you start the drug.
Talk with your doctor if you have questions about what to expect with Relenza treatment.
It’s important that you don’t use more Relenza than your doctor prescribes. For some medications, using more than the recommended amount may lead to harmful effects or overdose.
If you use more than the recommended amount of Relenza
Call your doctor right away if you believe you’ve used too much Relenza. Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.
Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.