NHS Direct Medicines Fact Sheet
Relenza® (zanamivir) Inhaler
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electronic medicines information sources offering practical advice and
selected facts that the call handler may find difficult to locate elsewhere.
The core NHS Direct electronic medicines information sources must be
consulted for detailed information on indications, warnings,
contraindications, doses, adverse effects and interactions in accordance
with the National Policy on Handling Medicines Calls (NP005).
General Information
Relenza® blocks the entry and release of influenza virions (individual
viruses) from cells in the respiratory tract. Unlike a vaccine which prepares
the immune system to quickly deal with exposure in the future, Relenza®
aims to slow the spread of the virus throughout the body. It does this by
stopping virions penetrating cells (in order to reproduce) and preventing
the release of new virions from cells that have been infected (1). Note that
Relenza® does not stop the virus from reproducing itself once a cell has
been infected.
Indications
Relenza® is indicated for adults and children 5 years of age and over.
It is not a cure, but it aims to:
 Prevent influenza from spreading by reducing the chance of close
contacts of confirmed or probable cases becoming infected.
 Ameliorate (reduce and shorten) the symptoms once infected.
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Despite the manufacturer’s statement in the Summary of Product
Characteristics (SPC), NICE has approved Relenza® for use in Residential
Nursing Homes and in adults over the age of 65 years (2,3).
Contraindications and restrictions on use
Contraindicated: People allergic to zanamivir or any of Relenza’s®
excipients including lactose (1).
Flu Prevention: At the time of writing Relenza® is indicated only for those
who had close contact during the period when the case was symptomatic
AND if the most recent exposure to the case occurred within the past 7
days. The Health Protection Agency provides information on who are
“close contacts” and the criteria for “confirmed infection” (4).
Warnings, Precautions and Important Interactions
Most people should be able to take Relenza® however the manufacturer
cautions its use in patients with severe asthma because of the risk of
bronchospasm (1). Such patients should have a fast acting bronchodilator
(e.g. salbutamol) available.
No clinically important drug or food interactions have been identified (1).
Patients can take it with their usual medicines.
Dose
For the treatment of symptoms in adults and children from the age of 5
years: two inhalations (2 x 5 mg) twice daily for five days. To be effective it
needs to be started within 48hrs of symptoms appearing in adults and
36hrs in children (1).
For preventing influenza in adults and children from the age of 5 years
who are deemed close contacts of confirmed or probable symptomatic
cases: two inhalations (2 x 5 mg) once daily for 10 days. Therapy should
Date last updated: 7 May 09 Review due: 7 May 11
Version: 2.0
begin as soon as possible and within 36 hours of exposure to an infected
person (1).
Dosage Forms and Supply Restrictions
Relenza® is a prescription only medicine (POM) available on the NHS for
those who have confirmed or probable infection and the close contacts of
symptomatic cases. In order for close contacts to be eligible they must
have been in close contact with the infected person while they had
symptoms and within the last seven days (4,5).
People who do not meet the NHS criteria may have obtained supplies by
private prescription.
Relenza® is a dry powder, diskhaler device. Each blister contains the
equivalent of 5mg of zanamivir (1). See the SPC for further details.
Common Side-effects
No common side-effects are expected.
Bronchospasm is mentioned in the SPC as a rare complication in patients
with severe asthma (1).
Time to effect
Relenza® reduces the duration of influenza symptoms by one and a half
days on average (1).
Driving, Machinery and Alcohol
Taking Relenza® should not further impair people’s ability to drive or
operate machinery. Relenza® is not expected to enhance the sedative
effects of alcohol (1).
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Timing with other inhaled medicines
Patients who use other inhaled medicines are advised to take them before
using Relenza® (1).
Pregnancy and Breastfeeding
Pregnancy: Although there is very little information about the safety of
Relenza® in human pregnancy, animal studies do not suggest there is a
risk to the foetus. Influenza during pregnancy can lead to pneumonia in
the mother and infection might pose a risk to the unborn baby. Overall the
benefits of Relenza® are likely to outweigh the risks (6,7).
Breastfeeding: Taking Relenza® is not a reason to stop breastfeeding.
Very small amounts pass into the breast milk but not enough to cause
concern. Breastfeeding can continue as normal while taking Relenza® (7).
References
1) Summary of Product Characteristics – Relenza 5mg/dose inhalation
powder. (zanamivir) GlaxoSmithKline. Last revision of text 1
October 2008 Accessed via http://emc.medicines.org.uk on 30 April
2009.
2) The National Institute for Health and Clinical Excellence (NICE)
Technology Appraisal Guidance 168. Amantadine, oseltamivir and
zanamivir for the treatment of influenza (review of NICE technology
appraisal guidance 58). February 2009. Accessed via
http://guidance.nice.org.uk on 29 April 2009.
3) The National Institute for Health and Clinical Excellence (NICE)
Technology Appraisal Guidance 158. Amantadine, oseltamivir and
zanamivir for the prophylaxis of influenza (review of NICE technology
appraisal guidance 67). September 2008. Accessed via
http://guidance.nice.org.uk on 29 April 2009.
Date last updated: 7 May 09 Review due: 7 May 11
Version: 2.0
4) Health Protection Agency. WHO Pandemic Alert Phase 5: Actions
and post exposure prophylaxis for close contacts of probable or
confirmed human case(s) of swine influenza A/H1. Accessed via
http://www.hpa.org.uk/ on 5 May 2009.
5) Martin J, editor. British National Formulary No 57. London: BMJ
Group and RPS Publishing; March 2009.
6) Anon. Zanamivir in Pregnancy. National Poisons Information Service
and the UK Teratology Information Service. Updated 06/05/09.
Accessed via www.toxbase.org on 7 May 2009.
7) Anon. Management of pregnant women during an influenza A
(H1N1) (Swine Flu) pandemic. National Poisons Information Service
and the UK Teratology Information Service. National Poisons
Information Service and the UK Teratology Information Service.
Updated 06/05/09. Accessed via www.toxbase.org on 7 May 2009.
8) Oseltamivir or zanamivir - Can mothers breastfeed after treatment for
influenza? Trent Medicines Information Service. Accessed via
http://www.nelm.nhs.uk/en/NeLM-Area/Evidence/Medicines-Q-A/Oseltamivir-or-zanamivir---Can-mothers-breastfeed-aftertreatment-for-influenza/ on 01 May 2009.
Quality Assurance
Search strategy
Standard in-house resources.
Prepared by
Wynn Pevreal
Principal Pharmacist
London Medicines Information Service
Contact
Med.info@nwlh.nhs.uk
Checked by
Alexandra Denby
Regional MI Manager
London Medicines Information Service
Date of check
April 30th 2009.
Updated
May 7th 2009 (NeLM weblinks, phrasing, updated references 4,6,7)
Wynn Pevreal
Produced by NHS Direct UKMI Working Group
Date last updated: 7 May 09 Review due: 7 May 11
Version: 2.0