Fexofenadine
Fexofenadine is an antihistamine drug used in the treatment of hayfever and similar allergy symptoms. It was developed as a successor of and alternative to terfenadine, an antihistamine with potentially fatal contraindications. Fexofenadine, like other second-generation antihistamines, does not readily enter the brain from the blood, and so causes less drowsiness than first generation histamine receptor antagonists; Fexofenadine hydrochloride (brand names include Allegra and Telfast) is an antihistamine drug used in the treatment of hayfever and similar allergy symptoms. It was developed as a successor of and alternative to terfenadine, an antihistamine with potentially fatal contraindications. Fexofenadine, like other second generation antihistamines, does not readily enter the brain from the blood, and so causes less drowsiness than first-generation histamine-receptor antagonists.