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Drugs reference index «Relenza»



Generic name: ZanamivirBrand names: Relenza

Why is Relenza prescribed?

Relenza speeds recovery from the flu. When started during the first 2 days of the illness, it hastens improvement by at least a day. It also can prevent the flu if treatment is started within 2 days after exposure to the virus. Relenza belongs to a class of antiviral drugs called neuraminidase inhibitors.

As the flu virus takes hold in the body, it forms new copies of itself and spreads from cell to cell. Neuraminidase inhibitors fight the virus by preventing the release of new copies from infected cells. Relenza is taken by inhaling the medication through the mouth.

Most important fact about Relenza

Relenza can prevent the flu as long as you continue taking Relenza, but getting a yearly flu shot is still the best way of avoiding the disease entirely. For older adults, those in high-risk situations such as health-care work, and people with an immune deficiency or respiratory disease, vaccination remains a must.

How should you take Relenza?

Relenza is delivered directly to the lungs by oral inhalation from a Diskhaler device. To benefit from the drug, you must begin taking it within 48 hours of feeling the first symptoms of flu, and must finish the entire 5-day course of treatment.

Be sure to take two doses on the first day, allowing at least 2 hours between them. On the following days, take a dose every 12 hours (morning and evening). Do not puncture a blister containing the drug until you are ready to use it.

Children should use Relenza only under the supervision of an adult.

  • If you miss a dose...Take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Do not take 2 doses at the same time.
  • Storage instructions...Store at room temperature.

What side effects may occur?

Symptoms experienced during Relenza therapy are virtually the same as those associated with untreated flu. Problems reported during clinical tests are listed below.

  • Side effects may include:Abdominal pain, bronchitis, cough, diarrhea, dizziness, ear infection, headache, fatigue, fever, hives, joint pain, muscle ache, nasal infection, nasal symptoms, nausea, sinus inflammation, throat infection, vomiting

Why should Relenza not be prescribed?

If Relenza gives you an allergic reaction, you cannot use Relenza.

Special warnings about Relenza

Relenza has been known to cause serious and potentially fatal breathing problems, especially in people who have asthma or other chronic pulmonary disorders. If you develop breathing difficulties such as wheezing or shortness of breath, stop taking Relenza and call your doctor immediately.

Relenza is generally not recommended for anyone with a chronic lung disease. If you do use it under these circumstances, be extremely cautious, and make sure that you have a fast-acting inhaled bronchodilator (a type of asthma medication such as albuterol) available and ready to use whenever you take it. If you use an inhaled bronchodilator regularly and have a dose scheduled at the same time as Relenza, use the bronchodilator first.

Relenza can also cause serious allergic reactions. If you experience swelling of the face, tongue, or throat, or develop a skin rash, stop taking Relenza and contact your doctor.

Serious bacterial infections may begin with flu-like symptoms or may coexist with the flu. Relenza has no effect on such infections.

Relenza has not been tested in people with medical conditions severe enough for possible hospitalization. Use it with caution if you have any kind of serious health problem in addition to the flu.

Possible food and drug interactions when taking Relenza

No interactions have been reported. If you regularly use an inhaled bronchodilator (a type of asthma medication) and have a dose scheduled at the same time as Relenza, use the bronchodilator first.

Special information if you are pregnant or breastfeeding

The effects of Relenza during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, inform your doctor. It is not known whether Relenza appears in breast milk. Caution is recommended if you are breastfeeding.

Recommended dosage for Relenza


Treatment of Influenza

The recommended dose is 2 inhalations (one 5-milligram blister per inhalation) twice a day, approximately 12 hours apart, for 5 days.

Relenza has not been studied for treating the flu in children younger than 7 years old.


Prevention of Influenza

The recommended dose is 2 inhalations (one 5-milligram blister per inhalation) once a day for 10 days. If there is a general outbreak of the flu in your community, your doctor may recommend that you continue taking Relenza for up to 28 days.

Relenza has not been studied for preventing the flu in children younger than 5 years old.


Substantially increased doses of Relenza have caused no increase in adverse reactions. Nevertheless, if you suspect an overdose of Relenza, it would be wise to check with your doctor.

  • Relenza Prescribing Information (FDA)
  • Relenza Consumer Overview
  • Relenza Advanced Consumer (Micromedex) - Includes Dosage Information
  • Relenza MedFacts Consumer Leaflet (Wolters Kluwer)
  • Zanamivir Professional Patient Advice (Wolters Kluwer)

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