NCIt definition : The R-enantiomer of the calcium channel blocker verapamil. Dexverapamil competitively
inhibits the multidrug resistance efflux pump P-glycoprotein (MDR-1), thereby potentially
increasing the effectiveness of a wide range of antineoplastic drugs which are inactivated
by MDR-1 mechanisms. This agent exhibits decreased calcium antagonistic activity and
toxicity compared to racemic verapamil. (NCI04);