Fexofenadine hydrochlorideProduct ingredient for Fexofenadine

Fexofenadine is an over-the-counter second-generation antihistamine used in the treatment of various allergic symptoms.¹⁰ It is selective for the H₁ receptor, carries little-to-no activity at off-targets, and does not cross the blood-brain barrier⁹ - this is in contrast to previous first-generation antihistamines, such as diphenhydramine, which readily bind to off-targets that contribute to side effects such as sedation.¹ Fexofenadine is the major active metabolite of terfenadine⁷ and is administered as a racemic mixture in which both enantiomers display approximately equivalent antihistamine activity.⁹