Terfenadine: A mixture of equipotent antihistamine enantiomers without a clear 'isomeric ballast'

Abstract

Terfenadine was the first non-sedating histamine H1 receptor antagonist and one of the most frequently prescribed H1 antihistamines. Terfenadine has one asymmetric centre in the molecule and is currently used as a racemate. Different methods and approaches for obtaining pure enantiomers of terfenadine are summarized and discussed in the present paper. Studies on antihistamine activity of the enantiomers, their side-effects on the central nervous system, calcium channel affinity and metabolism are also reviewed and analysed. © 1993 Periodicals Service Company.