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. Common side effects may. 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 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. The main active. Fexofenadine (Allegra) is an antihistamine that treats and prevents allergy symptoms. It blocks histamine to reduce your symptoms. What is Allegra? Allegra (fexofenadine) is an antihistamine used to treat allergy symptoms, including sneezing, itching, watery eyes, and a runny nose in adults and children. Allegra OTC is an antihistamine that is used to treat the symptoms of seasonal allergies (hay fever) in adults and children. Allegra OTC 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 120mg Tablet is an anti-allergy medicine. It is used to treat allergic rhinitis and chronic idiopathic urticaria. It relieves symptoms such as sneezing, runny nose, nasal congestion, itching, watery eyes, and hives. It works by blocking histamine, a substance that triggers allergic symptoms. Allegra 120mg Tablet is usually taken before. Allegra (Fexofenadine Hcl) may treat allergy, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison. Get fast-acting relief from seasonal allergies and symptoms like a runny nose, sneezing, itchy, watery eyes, and itchy nose or throat. Allegra ® kicks in within just one hour with 0% brain interference from drowsiness—that's right, it doesn't enter your brain and leave you feeling groggy. It is a common over-the-counter medication available under many brand names (including Allegra), as well as a generic drug. [11] Therapeutically, fexofenadine is a selective peripheral H 1 blocker.