Zanamivir


Generic Medicine Info
Indications and Dosage
Inhalation/Respiratory
Influenza A and B
Adult: As powder for oral inhalation: 10 mg (2 inhalations) bid for 5 days via inhalation device. Initiate treatment within 48 hours after onset of symptoms.
Child: As powder for oral inhalation: ≥5 years 10 mg (2 inhalations) bid for 5 days via inhalation device. Initiate treatment within 36 hours after onset of symptoms. Dosing recommendations may vary among individual products and between countries (refer to specific product guidelines).

Inhalation/Respiratory
Prophylaxis of influenza A and B
Adult: As powder for oral inhalation: Household or close contact exposure: 10 mg (2 inhalations) once daily for 10 days via inhalation device. Community outbreak: 10 mg (2 inhalations) once daily for up to 28 days via inhalation device. Initiate treatment within 36 hours of exposure.
Child: ≥5 years Same as adult dose. Dosing recommendations may vary among individual products and between countries (refer to specific product guidelines).

Intravenous
Influenza A and B
Adult: In patients with complicated and potentially life-threatening infection, resistant and/or unsuitable to other treatments: 600 mg bid for 5-10 days, via infusion over 30 minutes. Initiate treatment within 6 days of the onset of symptoms.
Child: In patients with complicated and potentially life-threatening infection, resistant and/or unsuitable to other treatments: As zanamivir hydrate: 6 months to <6 years 14 mg/kg bid. ≥6 years 12 mg/kg bid; max: 600 mg bid. All doses are given via infusion over 30 minutes. Treatment duration: 5-10 days.
Renal Impairment
Intravenous
Patients on intermittent haemodialysis or peritoneal dialysis, dose is given after dialysis session.

Adult and children ≥6 years weighing ≥50 kg:
CrCl (mL/min) Dosage
<15 Initially, 600 mg followed by 60 mg bid, to be started 48 hours after initial dose.
15-<30 Initially, 600 mg followed by 150 mg bid, to be started 24 hours after initial dose.
30-<50 Initially, 600 mg followed by 250 mg bid, to be started 12 hours after initial dose.
50-<80 Initially, 600 mg followed by 400 mg bid, to be started 12 hours after initial dose.

6 years to <18 years weighing <50 kg:
CrCl (mL/min) Dosage
<15 Initially, 12 mg/kg followed by 1.2 mg/kg bid, to be started 48 hours after initial dose.
15-<30 Initially, 12 mg/kg followed by 3 mg/kg bid, to be started 24 hours after initial dose.
30-<50 Initially, 12 mg/kg followed by 5 mg/kg bid, to be started 12 hours after initial dose.
50-<80 Initially, 12 mg/kg followed by 8 mg/kg bid, to be started 12 hours after initial dose.

6 months to <6 years weighing ≥42.8 kg:
CrCl (mL/min) Dosage
<15 Initially, 600 mg followed by 60 mg bid, to be started 48 hours after initial dose.
15-<30 Initially, 600 mg followed by 150 mg bid, to be started 24 hours after initial dose.
30-<50 Initially, 600 mg followed by 250 mg bid, to be started 12 hours after initial dose.
50-<80 Initially, 600 mg followed by 400 mg bid, to be started 12 hours after initial dose.

6 months to <6 years
weighing <42.8 kg:
CrCl (mL/min) Dosage
<15 Initially, 14 mg/kg mg followed by 1.4 mg/kg bid, to be started 48 hours after initial dose.
15-<30 Initially, 14 mg/kg followed by 3.5 mg/kg bid, to be started 24 hours after initial dose.
30-<50 Initially, 14 mg/kg followed by 5.8 mg/kg bid, to be started 12 hours after initial dose. 
50-<80 Initially, 14 mg/kg followed by 9.3 mg/kg bid, to be started 12 hours after initial dose.
Reconstitution
IV infusion: May infuse undiluted or dilute in 0.9% NaCl inj to a final concentration of ≥0.2 mg/mL.
Contraindications
Hypersensitivity.
Special Precautions
Patient with underlying respiratory disease (e.g. severe asthma, persistent asthma, severe COPD), unstable chronic illness. Immunocompromised, nursing home patients. Not a substitute for influenza vaccination. Renal impairment (IV). Children. Pregnancy and lactation.
Adverse Reactions
Significant: Allergic reactions (e.g. anaphylaxis, facial and oropharyngeal oedema, serious skin rashes [e.g. erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis]). Rarely, neuropsychiatric events in paediatric patients (e.g. confusion, delirium, hallucinations, seizure, self-injury); hepatocellular injury (IV).
Gastrointestinal disorders: Abdominal pain; diarrhoea (IV).
Investigations: Increased ALT, increased AST (IV).
Nervous system disorders: Vasovagal-like reactions (in patients with influenza symptoms), dizziness.
Respiratory, thoracic and mediastinal disorders: Dyspnoea, throat tightness or constriction.
Skin and subcutaneous tissue disorders: Rash, urticaria.
Potentially Fatal: Bronchospasm, decreased lung function.
Monitoring Parameters
Monitor for behavioural changes. Evaluate benefits and risks of continuing treatment. Monitor respiratory function.
Drug Interactions
May decrease the therapeutic effect of live or attenuated influenza virus vaccine.
Action
Description: Zanamivir selectively inhibits influenza virus neuraminidase surface enzyme, thus potentially altering the virus particle aggregation and release. It reduces reproduction of both influenza A and B viruses by suppressing the release of infective influenza virions from the epithelial cells of the respiratory tract.
Pharmacokinetics:
Absorption: Poorly absorbed from the gastrointestinal tract. Bioavailability: 2% (oral). Time to peak plasma concentration: 1-2 hours (inhalation).
Distribution: Widely deposited throughout the respiratory tract after oral inhalation. Volume of distribution: Approx 16 L. Plasma protein binding: <10%.
Excretion: Via urine (as unchanged drug); faeces (unabsorbed drug). Elimination half-life: 2.5-5.1 hours (oral inhalation); approx 2-3 hours (IV).
Chemical Structure

Chemical Structure Image
Zanamivir

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 60855, Zanamivir. https://pubchem.ncbi.nlm.nih.gov/compound/Zanamivir. Accessed July 27, 2021.

Storage
Powder for oral inhalation: Store below 30°C. Solution for infusion: Store diluted solution between 2-8°C for up to 24 hours.
MIMS Class
Antivirals
ATC Classification
J05AH01 - zanamivir ; Belongs to the class of neuraminidase inhibitors. Used in the treatment of viral infections.
References
Anon. Zanamivir. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 07/05/2021.

Buckingham R (ed). Zanamivir. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 07/05/2021.

Dectova 10 mg/mL Solution for Infusion (GlaxoSmithKline Trading Services Limited). European Medicines Agency [online]. Accessed 07/05/2021.

GlaxoSmithKline NZ Limited. Relenza Rotadisk 5 mg/blister Inhalation Powder data sheet 5 April 2018. Medsafe. http://www.medsafe.govt.nz. Accessed 07/05/2021.

Joint Formulary Committee. Zanamivir. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 07/05/2021.

Relenza 5 mg/dose, Inhalation Powder, Pre-Dispensed (Glaxo Wellcome UK Ltd). MHRA. https://products.mhra.gov.uk. Accessed 07/05/2021.

Relenza Powder (GlaxoSmithKline LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 07/05/2021.

Relenza Rotadisk (GlaxoSmithKline Pharmaceutical Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 07/05/2021.

Zanamivir. Gold Standard Drug Database in ClinicalKey [online]. Elsevier Inc. https://www.clinicalkey.com. Accessed Relenza.

Disclaimer: This information is independently developed by MIMS based on Zanamivir from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by MIMS.com
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