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.