Relenza (Zanamivir)

(℞) Prescription Required

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Relenza Diskhaler 5mg

Product of United Kingdom
Manufactured by: GlaxoSmithKline Inc.
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Relenza Diskhaler 5mg
Product of United Kingdom
Manufactured by GlaxoSmithKline Inc.
Select your dosage

Relenza (Zanamivir) Dosage and Side Effects

RELENZA is an antiviral medicine for the treatment of influenza and for reducing the chance of getting the flu in community and household settings.

Proper Use of this medication

Usual dose:

For the Treatment of Influenza:

You need to inhale two blisters in the morning and two blisters in the evening. You will use 1 ROTADISK disk each day for 5 days. RELENZA works best when you start taking it as soon as you begin to feel symptoms and no later than 2 days after flu symptoms start. Take the entire dosage (all 5 ROTADISK disks) of RELENZA even if you start to feel better before you've finished all your medicine.

For the Prevention of Influenza:

To reduce the chance of getting the flu, the usual dose is two blisters once daily for 10 or 28 days as prescribed by your doctor.

If you are scheduled to use an inhaled bronchodilator at the same time as RELENZA, you should use your bronchodilator first, before using RELENZA.


In case of drug overdose, contact a health care practitioner, hospital emergency department or regional Poison Control Centre immediately, even if there are no symptoms.

Missed dose:

If you miss a dose, don't worry. Take a 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 doctor or pharmacist and follow the advice given to you.

Side Effects

Some patients have had breathing problems while taking RELENZA. This can be very serious and needs treatment right away. Most of the patients who had this problem had asthma or COPD but some did not. If you have trouble breathing or have wheezing after your dose of RELENZA, stop taking RELENZA and seek medical attention immediately.

In studies, the most common side effects during treatment with RELENZA have been headaches, diarrhea, nausea, vomiting, nasal irritation, bronchitis, cough, sinusitis; ear, nose and throat infections and dizziness. Other side effects that have been reported, but are not as common include allergic reactions and rashes.

If you are feeling unwell when you take RELENZA you may faint or become lightheaded after inhaling RELENZA. You must sit down in a relaxed position before inhaling the dose of RELENZA, and you must only hold your breath for as long as is comfortable after inhaling the dose. If you are feeling unwell, you are advised to have someone with you while you are inhaling the dose of RELENZA.

People with influenza (the flu), particularly children and adolescents, may be at an increased risk of seizures, confusion, delirium, hallucinations, or abnormal behaviour 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 behaviour and a healthcare professional should be contacted immediately if the patient shows any signs of unusual behaviour.

Warnings and Precautions

Serious Warnings and Precautions

Some patients have had bronchospasm (wheezing) or serious breathing problems when they used RELENZA. Many but not all of these patients had asthma or chronic obstructive pulmonary disease. There is limited data on the use of RELENZA in patients with severe asthma or severe chronic obstructive pulmonary disease. Therefore, RELENZA is not generally recommended for such patients.

If you develop worsening respiratory symptoms such as wheezing or shortness of breath, stop using RELENZA and contact your doctor right away.

If you have chronic respiratory disease such as asthma or chronic obstructive pulmonary disease and your doctor 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.

Other kinds of infections can appear like influenza or occur along with influenza and need different kinds of treatment. Contact your doctor if you feel worse or develop new symptoms during or after treatment, or if your influenza symptoms do not start to get better.

BEFORE you use RELENZA talk to your doctor or pharmacist if:

  • you suffer from asthma or chronic respiratory disease.
  • Similar to other non-bronchodilator medications that are inhaled as a dry powder, a bronchospasm can occur when using RELENZA and a fast-acting inhaled bronchodilator (e.g. salbutamol) should be available if this occurs.
  • you are pregnant, or likely to become pregnant soon, or if you are breast feeding.
  • If you are pregnant or breast feeding, your doctor will help you decide whether you should take RELENZA.
  • you have any type of chronic condition including lung or heart disease.
  • you are allergic to lactose or milk protein.

Interactions with this medication

It is unlikely that RELENZA will interact with any medications you might be taking. Always be sure to tell your doctor what medications you are using.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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