Are allergra and zyrtec (cetirizine) the same?

Both antihistamines: Allegra (fexofenadine) and zyrtec (cetirizine) are both new generation antihistamines affecting h1 receptor. They are different compounds but essentially work the same way. They are both approved for allergic rhinitis and hives. Both come in various forms for treatment of children and adults. Time of onset for clinical relief of symptoms is about the same.