About levocetirizinea third-generation non-sedative h1 antagonist, antihistamine.mechanism of action of levocetirizinethis active enantiomer of cetrizine is a potent, nonsedative and selective h1 receptor antagonist. it antagonizes the allergic symptoms produced by histamines like runny nose, cold, cough etc. it also inhibit eotaxin-induced eosinophil tem through both dermal and lung micro vascular endothelial cells. so inhibit eosinophil chemotaxis and also inflammation caused by it.indications for levocetirizine1. rhinitis (seasonal and perennial) 2. idiopathic urticaria interactions for levocetirizinecoadministration with alcohol or other cns depressants may have additional cns depressant effect.