Generic Name: Fexofenadine Hcl
Brand Name: Allegra
Manufacturer: Aventis
Other Brand Names: Allegra, Alerfedine, Telfast

Allegra (Fexofenadine Hcl) is an oral, "second generation" antihistamine that is used to treat the signs and symptoms of allergy that are due to histamine. Histamine is a chemical that is responsible for many of the signs and symptoms of allergic reactions for example, swelling of the lining of the nose, sneezing & itchy eyes. Histamine is released from histamine-storing cells & then attaches to other cells that have receptors for histamine. The attachment of the histamine to the receptors causes the cell to be "activated," releasing other chemicals that produce the effects that we associate with allergy e.g., sneezing. Fexofenadine blocks the H1 receptor and thus prevents activation of H1 receptor-containing cells by histamine. Unlike the first generation antihistamines, fexofenadine and other second-generation antihistamines do not readily enter the brain from the blood & therefore they cause less drowsiness.