Xyzal or levocetirizine is in the anti-histamine class, similar to diphenhydramine (Benedryl), cetirizine (Zyrtec), desloratadine (Clarinex), fexofenadine
loratadine (Claritin). It helps treat allergy symptoms, such as itchy eyes and
running nose, by blocking the action of histamines.
It is available as a 5 mg breakable (scored) tablets, so you can cut the tablet in half and take the 2.5 mg dose if needed.