Azelastine Hydrochloride

**Semantic type:** Pharmacologic Substance

**Definition:** The hydrochloride salt form of azelastine, a phthalazinone derivative with antihistaminergic activity. Azelastine hydrochloride competes with histamine for the H1 receptor, thereby diminishing the actions of histamine on effector cells and decreasing the histamine-mediated symptoms of allergic reaction, such as bronchoconstriction, vasodilation, increased capillary permeability and spasmodic contractions of gastrointestinal smooth muscle.

**Synonyms:** - 1(2H)-Phthalazinone, 4-((4-Chlorophenyl)methyl)-2-(hexahydro-1-methyl-1H-azepin-4-yl)-, Monohydrochloride - AZELASTINE HYDROCHLORIDE - Astelin - Optivar - W-2979M