Azelastine hydrochloride is widely used as an antihistamine in the treatment of allergic conditions. It is commonly found in nasal sprays to alleviate symptoms of seasonal and perennial allergic rhinitis, such as sneezing, runny nose, and nasal congestion. The medication works by blocking histamine receptors, reducing the body's allergic response. Additionally, it is used in eye drops to manage allergic conjunctivitis, providing relief from itching, redness, and watery eyes. Its anti-inflammatory properties make it effective in managing both acute and chronic allergic reactions. Azelastine hydrochloride is often preferred due to its rapid onset of action and ability to provide long-lasting relief with minimal systemic side effects.