Relenza Zanamivir Flu Treatment

Relenza is the trade name of the prescription medicine Zanamivir as marketed by GlaxoSmithKline. It is used to treat and prevent an infection with the flu (influenza) virus.

How does Relenza work?

The flu is a highly contagious infection of the upper airways and respiratory tract. It is passed on via droplet infection, i.e. you can catch it from somebody who’s got the flu if they cough or sneeze, by shaking their hand or by touching a contaminated surface as the virus can survive for a while once outside the body. For this reason, you should not share any everyday utensils with somebody who has the flu and you should avoid bodily contact. Once inside the body, the virus replicates very quickly which leads to a quick spread thus a quick outbreak of the typical symptoms.

The virus requires a certain chemical substance to leave an infected host cell and move onto another. This enzyme is called neuramidase. Zanamivir inhibits its action which means the virus can no longer spread which allows the body’s immune system to fight the remaining pathogens.

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Is Relenza effective?

In healthy people, Relenza can considerably speed up recovery and reduce the severity of flu symptoms. To get the maximum benefit of the treatment, you need to start it within 48 hours after the first symptoms manifested themselves.

If you are not displaying flu symptoms but have been in contact with somebody who is, you can take Relenza preventatively to avoid getting ill yourself. In this case you should start using zanamivir within 36 hours after being exposed to the flu virus.

Neither seasonal nor pandemic strains have so far shown any resistance to Relenza according to the US Centers for Disease Control and Prevention which makes the drug highly effective.

How and when should I use Relenza?

Relenza comes in form of blistered round foil disks, each of which containing a very fine powder of 5mg Zanamivir. The bioavailability of Zanamivir is 2% which means that 2% of the 5mg per disk will be absorbed by the body.

The powder is inhaled via a special device called a diskhaler which pierces the blister, so the medicine is delivered directly to the lungs and respiratory tract, which is the initial infection site the flu virus targets. Use Relenza according to your prescribing doctor’s instructions. The medicine can be used to treat an acute infection with the flu when you are already ill as well as to prevent an infection with the flu if you’ve been in contact wit somebody who has got it. Together with Tamiflu, Relenza is a good staple medecine to have during a pandemic outbreak, such as the swine flu pandemic which is likely to return during the colder months this autumn and winter. To get the most out of our treatment with Relenza, you need to start using the medicine within 48 hours of either being exposed to the flu virus/developping first symptoms such as fever and muscle aches.

During last yea's swine flu outbreak, Zanamivir was successfully used by patient groups bearing a particular risk of flu complications such as pregnant women, elderly patients, chronically ill patients or patients suffering from liver disease.

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What are the side effects of Relenza?

Any medecine can cause potential side effects which may affect people in different ways. Most people respond well to Relenza and do not experience any side effects. Below is a list of reported zanamivir side effects which statistically affect less than 1 in 10.000 patients.

Bronchospasm (Narrowing of the airways)
Difficulty in breathing (dyspnoea)
Feeling of a tight throat
Rash or hives
Allergic reaction with facial swelling

Zanamivir is not known to have any toxic effects to the human organism and at present, none of the known influenza virus strains have shown to be resistant to the active ingredient.

Relenza Precautions

Use Relenza as instructed by your healthcare practitioner and do not consume the blisters orally, exclusively inhale them using the provided diskhaler. Zanamivir can on very rare occasions narrow the airways which can cause trouble breathing. If you experience this after taking Relenza, stop treatment immediately and consult a doctor without delay. If you are asthmatic, have your asthma inhaler to hand when undertaking treatment with Zanamivir so as to be able to counteract shortness of breath if it occurs.

Relenza should be used with caution in patients who suffer from asthma or chronic obstructive pulmonary disease (COPD).

Who should not use Relenza?

Please inform your prescribing doctor if you are knowingly allergic to any of the ingredients of Relenza or if you are affected by a rare hereditary condition known as galactose intolerance, the Lapp lactase deficiency, a glucose-galactose malabsorption or if you intolerant to Lactose. Relenza should not be given to children under the age of five.

While the potential risks of treatment with Zanamivir during pregnancy have not been fully studied, the medicine has been prescribed to expectant mothers during last year’s swine flu pandemic with success as, compared to Tamiflu, Relenza does not get released into the blood stream, it acts directly on the primary infection site i.e. the airways and respiratory tract. If you are pregnant, please consult your doctor before using Relenza.

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