The FDA has approved the use of Relenza (zanamivir for inhalation) for prevention (prophylaxis) of influenza in adults and children 5 years of age and older. Relenza, an antiviral medication, was previously approved for the treatment of influenza A and B virus infections in adults and children. Tamiflu (oseltamivir phosphate) previously was approved for both prevention and treatment of flu; today's approval of Relenza for prevention provides Americans with another option for the prevention of influenza A and B infections.
The effectiveness of Relenza in preventing seasonal influenza has been demonstrated in four large-scale studies comparing the drug with placebo. In two of these trials, the use of the drug substantially reduced the spread of influenza in the participating households where participants were five years of age or greater. In both of these trials, the proportion of households that developed symptoms confirmed to be flu was 19 percent for the placebo group and 4.1 percent for the Relenza group.