[{"from": "human", "value": "Provide a brief overview of this molecule. [C][N][Branch1][C][C][C][C][C@@H1][Branch1][N][C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][Cl][C][=C][C][=C][C][=N][Ring1][=Branch1]"}, {"from": "gpt", "value": "The molecule is an alkylamine, and first-generation histamine antagonist with anti-allergic activity. Dexchlorpheniramine competitively blocks H1 receptors, thereby preventing the actions of histamine on bronchial smooth muscle, capillaries and gastrointestinal (GI) smooth muscle. The antagonistic action of this agent blocks the activities of endogenous histamine, thereby preventing histamine-induced bronchoconstriction, vasodilation, increased capillary permeability, and GI smooth muscle spasms."}]