Cetirizine is the generic name for the brand name Zyrtec and is a medication that is used to treat moderate to severe allergies, cold symptoms or chronic hives.Cetirizine was approved by the FDA in September 1996 and was initially available via prescription only.n Canada, it is also available under another brand name, Reactine. Cetirizine belongs to the second generation antihistamine class and is similar to drugs such as azelastine (Astelin), fexofenadine (Allegra), and loratadine (Claritin).