Structural determinants for histamine H1 affinity, hERG affinity and QTc prolongation in a series of terfenadine analogs

In the late 1980’s reports linking the non-sedating antihistamines terfenadine and astemizole with torsades de pointes, a form of ventricular tachyarrhythmia that can degenerate into ventricular fibrillation and sudden death, appeared in the clinical literature. A substantial body of evidence demonstrates that the arrhythmogenic effect of these cardiotoxic antihistamines, as well as a number of structurally related compounds, results from prolongation of the QT interval due to suppression of specific delayed rectifier ventricular K+ currents via blockade of the hERG-IKr channel. In order to better understand the structural requirements for hERG and H1 binding for terfenadine, a series of analogs of terfenadine has been prepared and studied in both in vitro and in vivo hERG and H1 assays.

Graphical abstractA series of analogs of terfenadine has been prepared to probe the structural requirements for hERG and H1 binding affinity.Figure optionsDownload full-size imageDownload as PowerPoint slide