NCIt definition : The dihydrochloride salt form of the active levorotatory enantiomer of cetirizine,
levocetirizine; a third generation, non-sedating, selective histamine H1 receptor
antagonist, with antihistamine, anti-inflammatory and potential anti-angiogenic activities.
Levocetirizine competes with endogenous histamine for binding at peripheral H1-receptor
sites on the effector cell surface. This prevents the negative symptoms associated
with histamine release and an allergic reaction. In addition, as histamine plays an
important role in angiogenesis during an allergic inflammatory reaction, blocking
the action of histamine may modulate the expression of proangiogenic factors and thus
may prevent angiogenesis. As a third-generation histamine H1 receptor antagonist,
levocetirizine has fewer side effects than most second-generation antihistamines.;