First approved by the FDA 11 years ago, Xyzal was only available with a prescription until February 2017, when drugstores started stocking it over the counter as well, under the name Xyzal Allergy 24HR. Let’s see how Xyzal stacks up against other popular antihistamines.     Identical: Prescription Xyzal vs. OTC Xyzal Over-the-counter (OTC) Xyzal