Drugs List

Therapeutic Indications

Uses

Post-exposure prophylaxis of influenza
Seasonal prophylaxis of influenza
Treatment of influenza A
Treatment of influenza B

Treatment of influenza A and influenza B
Zanamivir can be used in adults and children aged 5 years and above who present with symptoms of influenza when influenza is circulating in the community.

Prevention of influenza A and influenza B
Zanamivir can be used for post-exposure prophylaxis of influenza A and influenza B in adults and children aged 5 years and above following contact with a clinically diagnosed case in a household.

In exceptional circumstances, zanamivir may be considered for seasonal prophylaxis of influenza A and influenza B during a community outbreak. Circumstances may include where the circulating strain and vaccine strain differ, or in a pandemic situation.

Community-based virological surveillance schemes, including those run by the Health Protection Agency and the Royal College of General Practitioners should be used to indicate when influenza is circulating in the community.

Contraindications

Children under 5 years
Hypersensitivity to milk protein (contaminant of lactose excipient)
Within 2 weeks of administration of live influenza virus vaccine
Breastfeeding
Galactosaemia

Precautions and Warnings

Chronic illness
Patients over 65 years
Chronic obstructive pulmonary disease
Chronic respiratory impairment
Glucose-galactose malabsorption syndrome
Immunodeficiency syndromes
Lactose intolerance
Pregnancy
Severe asthma

Administer other inhaled drugs first
Not a substitute for annual influenza vaccination in at-risk patients
Contains lactose
Use designated delivery device only
May cause respiratory depression
Monitor patients for behavioural changes
Monitor patients with bronchial asthma
May cause bronchospasm
Discontinue if bronchospasm or decreased respiratory function occur

The use of zanamivir for the treatment and prevention of influenza should take into account official recommendations, the variability of epidemiology and the impact of influenza in different geographical areas and patients populations.

The efficacy of zanamivir in preventing influenza in a nursing home setting has not been demonstrated.

Concurrent treatments for persistent asthma or severe chronic obstructive pulmonary disease should be optimised during treatment with zanamivir. These patients should be informed of the potential risk of bronchospasm during zanamivir treatment, and they should have a fast-acting bronchodilator available. Patients on maintenance inhaled bronchodilation therapy should be advised to use their bronchodilators before taking zanamivir.

Pregnancy and Lactation

Pregnancy

Use zanamivir with caution in pregnancy.
Manufacturers recommend that it is preferable to avoid the use of inhaled zanamivir, unless the potential benefit to the mother significantly outweighs the possible risk to the foetus.
It is unknown if zanamivir crosses the human placenta. The molecular weight (about 332), combined with the lack of metabolism and plasma protein binding and the moderately long elimination half-life, suggest that zanamivir will cross the human placenta (Briggs, 2015).
Animal studies have shown the placental transfer of zanamivir. Malformations, embryotoxicity or other alterations have not been seen when high doses were administered.
Experience and the presence of low systemic concentrations, make it unlikely that there is increased embryotoxic or fetotoxic risk (Schaefer 2015).

Lactation

Zanamivir is contraindicated during breastfeeding.
Manufacturers state that a risk to the breastfed infant cannot be excluded and that a decision must be made whether to discontinue breastfeeding or to discontinue/abstain from zanamivir therapy.
It is not known if zanamivir is excreted in human breast milk. The molecular weight (about 332), moderately long elimination half-life, and the lack of metabolism and plasma protein binding suggest that the drug will be excreted into breast milk. However, zanamivir is poorly absorbed orally (Briggs, 2015).
There is no exact information on the use of inhaled zanamivir, however, the limited systemic intake and minimal oral bioavailability allow the assumption that there is no relevant transfer to the breastfed infant (Schaefer 2015).
LactMed have indicated that zanamivir is not likely to reach the bloodstream of the infant in clinically important amounts. One group of authors estimated that an exclusively breastfed 5 kg infant would receive about 0.075 mg daily in breast milk after an inhaled maternal dose of 10 mg, which is less than 1% of the dose in older children.

Side Effects

Allergic reaction
Anaphylactic reaction
Anaphylactoid reaction
Angioedema
Behavioural disturbances
Bronchospasm
Convulsions
Dehydration
Delirium
Dyspnoea
Erythema multiforme
Facial oedema
Fever
Hallucinations
Impaired consciousness
Neuropsychiatric disturbances
Oropharyngeal oedema
Rash
Respiratory insufficiency
Stevens-Johnson syndrome
Throat tightness
Toxic epidermal necrolysis
Urticaria

Presentation

Inhalation powder containing zanamivir.

Drugs List

Therapeutic Indications

Uses

Post-exposure prophylaxis of influenza
Seasonal prophylaxis of influenza
Treatment of influenza A
Treatment of influenza B

Treatment of influenza A and influenza B
Zanamivir can be used in adults and children aged 5 years and above who present with symptoms of influenza when influenza is circulating in the community.

Prevention of influenza A and influenza B
Zanamivir can be used for post-exposure prophylaxis of influenza A and influenza B in adults and children aged 5 years and above following contact with a clinically diagnosed case in a household.

In exceptional circumstances, zanamivir may be considered for seasonal prophylaxis of influenza A and influenza B during a community outbreak. Circumstances may include where the circulating strain and vaccine strain differ, or in a pandemic situation.

Community-based virological surveillance schemes, including those run by the Health Protection Agency and the Royal College of General Practitioners should be used to indicate when influenza is circulating in the community.

Dosage

Begin treatment as soon as possible after onset of symptoms (within 48 hours for adults and 36 hours for children).
For the prevention of influenza, zanamivir should be administered as soon as possible and within 36 hours of exposure to an infected individual.

Adults

Children

Contraindications

Children under 5 years
Hypersensitivity to milk protein (contaminant of lactose excipient)
Within 2 weeks of administration of live influenza virus vaccine
Breastfeeding
Galactosaemia

Precautions and Warnings

Chronic illness
Patients over 65 years
Chronic obstructive pulmonary disease
Chronic respiratory impairment
Glucose-galactose malabsorption syndrome
Immunodeficiency syndromes
Lactose intolerance
Pregnancy
Severe asthma

Administer other inhaled drugs first
Not a substitute for annual influenza vaccination in at-risk patients
Contains lactose
Use designated delivery device only
May cause respiratory depression
Monitor patients for behavioural changes
Monitor patients with bronchial asthma
May cause bronchospasm
Discontinue if bronchospasm or decreased respiratory function occur

The use of zanamivir for the treatment and prevention of influenza should take into account official recommendations, the variability of epidemiology and the impact of influenza in different geographical areas and patients populations.

The efficacy of zanamivir in preventing influenza in a nursing home setting has not been demonstrated.

Concurrent treatments for persistent asthma or severe chronic obstructive pulmonary disease should be optimised during treatment with zanamivir. These patients should be informed of the potential risk of bronchospasm during zanamivir treatment, and they should have a fast-acting bronchodilator available. Patients on maintenance inhaled bronchodilation therapy should be advised to use their bronchodilators before taking zanamivir.

Pregnancy and Lactation

Pregnancy

Use zanamivir with caution in pregnancy.
Manufacturers recommend that it is preferable to avoid the use of inhaled zanamivir, unless the potential benefit to the mother significantly outweighs the possible risk to the foetus.
It is unknown if zanamivir crosses the human placenta. The molecular weight (about 332), combined with the lack of metabolism and plasma protein binding and the moderately long elimination half-life, suggest that zanamivir will cross the human placenta (Briggs, 2015).
Animal studies have shown the placental transfer of zanamivir. Malformations, embryotoxicity or other alterations have not been seen when high doses were administered.
Experience and the presence of low systemic concentrations, make it unlikely that there is increased embryotoxic or fetotoxic risk (Schaefer 2015).

Lactation

Zanamivir is contraindicated during breastfeeding.
Manufacturers state that a risk to the breastfed infant cannot be excluded and that a decision must be made whether to discontinue breastfeeding or to discontinue/abstain from zanamivir therapy.
It is not known if zanamivir is excreted in human breast milk. The molecular weight (about 332), moderately long elimination half-life, and the lack of metabolism and plasma protein binding suggest that the drug will be excreted into breast milk. However, zanamivir is poorly absorbed orally (Briggs, 2015).
There is no exact information on the use of inhaled zanamivir, however, the limited systemic intake and minimal oral bioavailability allow the assumption that there is no relevant transfer to the breastfed infant (Schaefer 2015).
LactMed have indicated that zanamivir is not likely to reach the bloodstream of the infant in clinically important amounts. One group of authors estimated that an exclusively breastfed 5 kg infant would receive about 0.075 mg daily in breast milk after an inhaled maternal dose of 10 mg, which is less than 1% of the dose in older children.

Side Effects

Allergic reaction
Anaphylactic reaction
Anaphylactoid reaction
Angioedema
Behavioural disturbances
Bronchospasm
Convulsions
Dehydration
Delirium
Dyspnoea
Erythema multiforme
Facial oedema
Fever
Hallucinations
Impaired consciousness
Neuropsychiatric disturbances
Oropharyngeal oedema
Rash
Respiratory insufficiency
Stevens-Johnson syndrome
Throat tightness
Toxic epidermal necrolysis
Urticaria

Overdosage

It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

The following number will direct the caller to the relevant local centre (0844) 892 0111

Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

Further Information

Last Full Review Date: August 2016

Reference Sources

Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.

Summary of Product Characteristics: Relenza 5mg/dose inhalation powder. GlaxoSmithKline UK. Revised November 2018.

US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
Available at: https://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT
Zanamivir. Last revised: 03 December 2018
Last accessed: 25 March 2019

NICE Evidence Services Available at: www.nice.org.uk Last accessed: 21 October 2021