Allegra (fexofenadine) is an antihistamine used to treat allergy symptoms, including sneezing, itching, watery eyes, and a runny nose in adults and children. Allegra can also be used to treat hives caused by a condition called chronic idiopathic urticaria in adults and children over 12 years of age. Allegra products are commonly used to treat allergy symptoms such as runny nose, sneezing, itchy/watery eyes, itchy nose or throat, hives, nasal congestion, and sinus pressure. Allegra (fexofenadine) is a non-drowsy antihistamine used for seasonal allergic rhinitis and chronic idiopathic urticaria. Compared with first-generation agents, it has minimal CNS penetration and is less sedating, making it suitable for daytime use and tasks that require alertness. While some other oral antihistamines may cause you to be drowsy, Allegra® won't. Fexofenadine, the active ingredient in Allegra ®, provides non-drowsy allergy relief with 0% brain interference, relieving allergy symptoms like sneezing, runny nose and itchy eyes. Allegra 24 Hour Allergy is also used to treat skin itching and hives caused by a condition called chronic idiopathic urticaria in adults and children at least 6 years old. Allegra allergy relief medicine starts working in one hour for relief from sneezing, runny nose, itchy and watery eyes, and itchy nose or throat. One pill provides 24-hour allergy relief that doesn’t make you drowsy and affect your normal brain function. Allegra allergy relief medicine starts working in one hour for relief from sneezing, runny nose, itchy and watery eyes, and itchy nose or throat. One pill provides 24-hour allergy relief that doesn’t make you drowsy and affect your normal brain function. Allegra allergy relief medicine starts working in one hour for relief from sneezing, runny nose, itchy and watery eyes, and itchy nose or throat. One pill provides 24-hour allergy relief that doesn’t make you drowsy and affect your normal brain function. Some allergy relief medications enter your brain, making you feel tired and sluggish, but Allegra ® is different. Unlike other antihistamines and because of its size, fexofenadine won't enter your brain so you stay clear-headed and alert while getting non-drowsy allergy relief. Overview: Fexofenadine is an antihistamine that is taken to help treat allergy symptoms, such as a runny nose, itchy or watery eyes, sneezing, or an itchy nose or throat.