Definition

The hydrochloride salt form of fexofenadine, a carboxylated metabolic derivative of terfenadine and third generation selective histamine H1-receptor antagonist with antihistaminic and non-sedative effects. Fexofenadine competitively binds peripheral H1-receptors, thereby stabilizing an inactive conformation of the receptor. Consequently histamine binding and activity as a result of mast-cell degranulation followed by the release of multiple inflammatory mediators, such as interleukins, prostaglandin and leukotriene precursors, is blocked, thereby preventing the triggering of pro-inflammatory pathways.