Efficacy and safety of azelastine nasal spray for the treatment of allergic rhinitis.

Azelastine hydrochloride is a nasally administered antihistamine that is effective and safe for the treatment of perennial and seasonal allergic rhinitis. In addition to acting as a histamine H1-receptor antagonist, azelastine also inhibits the production or release of many chemical mediators of the allergic response such as leukotrienes, free radicals, and cytokines. After nasal administration, azelastine is systemically absorbed with a bioavailability of about 40%. The side effects of azelastine are drowsiness, headache, and bitter taste. Azelastine has a rapid onset of action with a benefit in about 2 hours and a prolonged duration of activity (12 to 24 hours). Studies have shown azelastine to be more effective than placebo in terms of reduction of the major and total symptom complexes of allergic rhinitis. Comparison studies have demonstrated that azelastine is as effective as ebastine, loratadine, cetirizine hydrochloride, and terfenadine at symptom reduction, with varying results when compared with the corticosteroids budesonide and beclomethasone. Although there are conflicting studies, some have demonstrated that azelastine reduces the nasal congestion of allergic rhinitis. This feature that distinguishes it from oral antihistamines is of great interest because corticosteroids are known to be quite effective for the relief of nasal congestion, whereas the antihistamines are effective for the sneezing, itchy eyes, itchy nose, and watery eyes, but not the congestion. Azelastine nasal spray seems to be an efficacious treatment for allergic rhinitis with a rapid onset and long duration of activity, but without the systemic adverse effects of traditional sedating antihistamines.