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zanamivir (Relenza)

Indications: 1) influenza a) treatment of influenza A & influenza B b) prophylaxis for influenza A & influenza B c) marginal benefit in prevention & treatment of influenza [9] 2) effective against H1N1 virus 3) FDA approved for use in adults & children >= 7 years Contraindications: - avoid in patients with asthma or COPD Benefit/risk: - small benefit for preventing influenza-like illness [9] - number needed to treat: 51 - number needed to harm - 7 for nausea; 37 for vomiting [10] Dosage: 1) 2 inhalations BID for 5 days 2) start therapy within 2 days of onset 3) prophylaxis: 4-6 weeks Powder: (Dry), use only with supplied inhaler [5] Pharmacokinetics: - elimination renal Adverse effects: 1) may trigger bronchospasm 2) nausea, vomiting [10] 3) reports of delirium/abnormal behavior leading to injury [4] Mechanism of action: 1) neuraminidase inhibitor 2) reduce the severity & duration of flu symptoms 3) effective if administered early [8] Notes: - oseltamivir & zanamivir are modestly effective for symptoms of influenza in otherwise healthy adults - when used prophylactically, they have no effect against in preventing influenza-like illness or asymptomatic influenza - the drugs reduce influenza's symptoms by about a day - benefit for very ill people in hospital is without supporting data [6]

Interactions

drug interactions drug adverse effects of neuraminidase inhibitor(s)

Related

neuraminidase oseltamivir (Tamiflu)

General

neuraminidase inhibitor

Properties

INHIBITS: neuraminidase

Database Correlations

PUBCHEM correlations

References

  1. Prescriber's Letter 6(11) Nov 1999
  2. Prescriber's Letter 7(8):43 2000
  3. Prescriber's Letter 11(1):1 2004
  4. FDA MedWatch http://www.fda.gov/medwatch/safety/2008/safety08.htm#Relenza
  5. Prescriber's Letter 16(11): 2009 CHART: Tamiflu Expiration Date Extension COMMENTARY: Potential Medication Errors with Tamiflu Oral Suspension COMMENTARY: 2009-2010 Influenza Season: Issues Concerning Tamiflu and Relenza PDF: Tamiflu Emergency Compounding Detail-Document#: 251104 (subscription needed) http://www.prescribersletter.com
  6. Jefferson T et al Neuraminidase inhibitors for preventing and treating influenza in healthy adults: systematic review and meta-analysis BMJ 2009;339:b5106 PMID: 19995812 http://www.bmj.com/cgi/content/full/339/dec07_2/b5106
  7. Medical Knowledge Self Assessment Program (MKSAP) 15, American College of Physicians, Philadelphia 2009
  8. Muthuri SG et al. Impact of neuraminidase inhibitor treatment on outcomes of public health importance during the 2009-2010 influenza A (H1N1) pandemic: A systematic review and metaanalysis in hospitalized patients. J Infect Dis 2013 Feb 15; 207:553. PMID: 23204175 - Aoki FY and Hayden FG. The beneficial effects of neuraminidase inhibitor drug therapy on severe patient outcomes during the 2009-2010 influenza A virus subtype H1N1 pandemic. J Infect Dis 2013 Feb 15; 207:547. PMID: 23204176
  9. Heneghan CJ et al Zanamivir for influenza in adults and children: systematic review of clinical study reports and summary of regulatory comments. BMJ 2014;348:g2547 PMID: 24811412 http://www.bmj.com/content/348/bmj.g2547 - Krumholz HM and Hines HH Neuraminidase inhibitors for influenza BMJ 2014;348:g2548 PMID: 24811413 http://www.bmj.com/content/348/bmj.g2548 - Jefferson T, Jones MA, Doshi P et al Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children. Cochrane Database Syst Rev. 2014 Apr 10;4:CD008965 PMID: 24718923
  10. The NNT: Neuraminidase Inhibitors Given for Influenza. http://www.thennt.com/nnt/neuraminidase-inhibitors-for-influenza/