Desloratadine is an antihistamine medication used to relieve symptoms of allergies, such as sneezing, runny nose, itching, and watery eyes. It works by blocking the effects of histamine, which is a substance produced by the body in response to allergens. Desloratadine is considered a second-generation antihistamine, which means that it has fewer side effects compared to older antihistamines. It is available in tablet, syrup, and orally disintegrating tablet forms, and is typically taken once daily. Desloratadine is sold under various brand names, including Clarinex, Desloratidine Sandoz, and Aerius.