NCIt definition : The maleate salt form of dexchlorpheniramine, an alkylamine, and first-generation
histamine antagonist with anti-allergic activity. Dexchlorpheniramine maleate competitively
blocks H1 receptors, thereby preventing the actions of histamine on bronchial smooth
muscle, capillaries and gastrointestinal (GI) smooth muscle. This prevents histamine-induced
bronchoconstriction, vasodilation, increased capillary permeability, and GI smooth
muscle spasms.;