Allegra is a powerful antihistamine which gives you 24 hours of the fastest nondrowsy relief from indoor and outdoor allergy symptoms, including: sneezing, runny nose, itchy, watery eyes, and itchy nose and throat. This Allegra allergy medication has 180 milligrams of fexofenadine HCl per tablet and not only relieves seasonal allergic rhinitis but also reduces the severity of the symptoms associated with hives (i.e. idiopathic urticaria). Allegra is a type of antihistamine that is not associated with inducing drowsiness.