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Zanamivir. No noticeable progress against influenza
Abstract:
* Zanamivir (Relenza((R)), Glaxo Wellcome) an antiviral drug, is marketed for treatment of influenza during outbreaks.* The clinical file consists mainly of three doubleblind, placebo-controlled trials.* When administered to patients with symptoms of influenza, at an inhaled dose of 10 mg twice daily, zanamivir has no clear benefit, or very limited benefit (hastening clinical recovery by 0.7 to 1.5 days) provided treatment is started within 30 hours of symptom onset. Zanamivir seems to act on influenza virus types A and B. No reliable data are available on the effect of zanamivir on overall intensity of symptoms during episodes or on time required to resume normal activities. The value of zanamivir for preventing complications in people at risk remains to be demonstrated.* Zanamivir has not been compared with another antiviral drug, amantadine, which has been available for nearly 30 years for the same indication. The two drugs have similar efficacy regarding time to recovery. Amantadine acts only on influenza virus type A.* In clinical trials, incidence of adverse events was not significantly higher with zanamivir than with placebo, but some patients with asthma and chronic obstructive airways disease experienced bronchospasm following zanamivir administration. Amantadine, which has been in use for about 30 years, has a relatively good safety profile.* Zanamivir is a costly preparation.
Insights
Zanamivir offers minimal benefit for influenza recovery, shortening illness by only 1-1.5 days when started early. Its efficacy and safety profile require further demonstration, especially compared to older antivirals like amantadine.
Area of Science:
- * Virology and infectious disease research.
- * Clinical pharmacology and drug efficacy studies.
Background:
- * Zanamivir (Relenza) is an antiviral medication approved for influenza treatment.
- * Influenza virus poses a significant public health concern, necessitating effective treatment options.
Purpose of the Study:
- * To evaluate the clinical efficacy and safety of zanamivir for influenza treatment.
- * To compare zanamivir's benefits against placebo and potentially other antiviral drugs.
Main Methods:
- * Analysis of three double-blind, placebo-controlled clinical trials.
- * Assessment of zanamivir's impact on symptom duration and recovery time.
Main Results:
- * Zanamivir provided limited clinical benefit, shortening recovery by 0.7–1.5 days when initiated within 30 hours of symptom onset.
- * Efficacy was observed against influenza A and B viruses, but data on symptom intensity and return to normal activities were lacking.
- * No significant increase in adverse events compared to placebo, though bronchospasm occurred in some patients with respiratory conditions.
Conclusions:
- * Zanamivir demonstrates minimal to limited clinical benefit in influenza treatment.
- * Further research is needed to establish its value in preventing complications and for comparison with other antivirals like amantadine.
- * Safety concerns, particularly bronchospasm in susceptible individuals, warrant consideration alongside its cost-effectiveness.