High Quality Content by WIKIPEDIA articles! Azelastine is a potent, second-generation, selective, histamine antagonist (histamine-H1-receptor antagonist) manufactured by MedaPharma. According to the Allergic Rhinitis and its Impact on Asthma (ARIA) treatment guidelines, intranasal anti-histamines are recommended for the first line therapy of mild intermittent, moderate/severe intermittent and mild persistent rhinitis (new classification system for rhinitis).