Zanamivir (Relenza)

Indications

Influenza Treatment (see Influenza Virus, [[Influenza Virus]])

  • Indications: indicated for treatment in patients >7 y/o
  • Clinical Efficacy of Influenza Treatments
    • Systematic Review and Meta-Analysis of Neuraminidase Inhibitors (Annals Int Med, 2012) [MEDLINE]
      • In High-Risk Populations, Oral Oseltamivir Decreased Mortality Rate (Odds Ratio: 0.23), Hospitalization (Odds Ratio: 0.75), and Duration of Symptoms (From 45 hrs -> 33 hrs)
      • Earlier Treatment with Oral Oseltamivir (Within 48 hrs) was Associated with Better Outcomes
      • Inhaled Zanamavir Decreased Symptom Duration (From 28 hrs -> 23 hrs) and Hospitalization (Odds Ratio: 0.66), But Had More Complications
      • No Differences Between Oseltamivir and Zanamavir
      • Oral Amantadine Decreased Mortality and Pneumonia: data from single study only
    • Cochrane Database Systematic Review of Efficacy of Neuraminidase Inhibitors in Influenza (Cochrane Database Syst Rev, 2014) [MEDLINE]
      • Time to First Symptom Alleviation
        • Oseltamavir Decreased the Time to First Alleviation of Symptoms in Adults by 16.8 hrs (Time to First Alleviation of Symptoms Decreased From 7.0 -> 6.3 Days): effect was observed in healthy children, but no effect was observed in asthmatic children
        • Zanamavir Decreased the Time to First Alleviation of Symptoms in Adults by 0.60 days (Mean Duration of Symptoms Decreased From 6.6 -> 6.0 Days): no effect was observed in children
      • Hospitalizations
        • Oseltamavir Had No Effect on Hospitalization Rate in Adults/Children: prophylaxis also had no no effect on hospitalizations
        • Zanamavir Hospitalization Rate was Not Reported
      • Serious Influenza Complications
        • Oseltamavir Did Not Decrease Serious Influenza Complications in Adults/Children: insufficient data to determine effect of oseltamavir prophylaxis on serious complications
        • Zanamavir Did Not Decrease Serious Influenza Complications in Adults: prophylaxis also had no no effect on serious complications
      • Pneumonia
        • Oseltamavir Decreased the Investigator-Reported, Unverified Pneumonia Rate: however, effect was not significant in trials which used more detailed diagnostic form for pneumonia (and no trials reported effect on radiologically-confirmed pneumonia)
        • Oseltamavir Prophylaxis Had No Effect on Self-Reported, Investigator-Mediated, Unverified Pneumonia Rate in Adults
        • Zanamavir Had No Effect on Self-Reported or Radiologically-Confirmed Pneumonia
        • Zanamavir Prophylaxis Decreased the Self-Reported, Investigator-Mediated, Unverified Pneumonia Rate in Adults
      • Bronchitis/Sinusitis/Otitis Media
        • Oseltamavir Had No Effect on the Risk of Bronchitis in Adults
        • Zanamavir Decreased the Risk of Bronchitis in Adults
        • Neither Oseltamavir/Zanamavir Decreased Rates of Sinusitis/Otitis Media in Adults/Children
      • Prophylaxis
        • Oseltamavir/Zanamavir Prophylaxis Decreased the Risk of Symptomatic Influenza
      • Conclusions
        • Oseltamavir/Zanamavir Have Small, Non-Specific Effects on Decreasing the Time to Alleviation of Symptoms in Adults, But Not in Asthmatic Children
        • Oseltamavir/Zanamavir Prophylaxis Decrease the Risk of Symptomatic Influenza
        • Trials Do Not Settle the Question of Whether Influenza Complications of Influenza (Pneumonia) are Reduced, Because of a Lack of Diagnostic Definitions
        • The Lower Bioavailability of Zanamivir May Explain its Lower Toxicity, as Compared to Oseltamivir

Influenza Prophylaxis (see Influenza Virus, [[Influenza Virus]])

  • Indications:

Pharmacology

  • Neuraminidase Inhibitor
    • Activity: Influenza A + B

Metabolism

  • xxx

Adminsitration

  • Inhalation
    • Treatment: 10 mg (2 Inhalations) BID (child >13 y/o and adult)
    • Propylaxis: 10 mg (2 Inhalations) qday (child >13 y/o and adult)
  • Intravenous: xxx

Dose-Adjustment

  • Hepatic: xxx
  • Renal: xxx

Adverse Effects

Pulmonary Adverse Effects

Other Adverse Effects

  • xxx

References

  • Antiviral agents for the treatment and chemoprophylaxis of influenza—recommendations of the Advisory Committee on Immunization Practices (ACIP).  MMWR Recomm Rep.  2011;60(1):1–24 [MEDLINE]
  • Antivirals for Treatment of Influenza: A Systematic Review and Meta-analysis of Observational Studies. Ann Intern Med. 2012;156:512-524 [MEDLINE]
  • A prospective intervention study on higher-dose oseltamivir treatment in adults hospitalized with influenza a and B infections. Clin Infect Dis. 2013 Dec;57(11):1511-9. doi: 10.1093/cid/cit597. Epub 2013 Sep 17 [MEDLINE]
  • Oseltamivir and inhaled zanamivir as influenza prophylaxis in Thai health workers: a randomized, double-blind, placebo-controlled safety trial over 16 weeks. J Antimicrob Chemother. Mar 2013; 68(3): 697–707. Published online Nov 9, 2012. doi: 10.1093/jac/dks418 [MEDLINE]
  • Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children. Cochrane Database Syst Rev. 2014 Apr 10;4:CD008965. doi: 10.1002/14651858.CD008965.pub4.
    [MEDLINE]
  • Prevention and Control of Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices, United States, 2015-16 Influenza Season. MMWR Morb Mortal Wkly Rep. 2015 Aug 7;64(30):818-25 [MEDLINE]