Double-blind assessment of azelastine in the treatment of perennial allergic rhinitis.

Azelastine is a chemically novel multifunctional antiallergy investigational drug capable of inhibiting mast-cell activation and the synthesis and/or release of chemical mediators of the upper and lower airway inflammatory response. In previous controlled clinical trials, azelastine was shown to be effective in treating the symptoms of both seasonal allergic rhinitis and perennial allergic rhinitis. The objective of this 8-week double-blind trial was to evaluate further azelastine's efficacy and safety in improving the symptoms of perennial allergic rhinitis over a prolonged period of treatment.