Both loratadine and levocetirizine hydrochloride are antihistamines and their effects are actually similar, so they should not be used at the same time, otherwise they will lead to overlapping medications. The difference is that loratadine tablets mainly relieve systemic and local symptoms in patients with chronic urticaria and perennial allergic rhinitis, while levocetirizine hydrochloride tablets are more effective for allergic symptoms caused by episodic reactions to disease. Central nervous system depression such as dizziness and drowsiness may occur after oral administration of loratadine tablets, but levocetirizine hydrochloride central nervous system depression is relatively small.