Potent and selective L-type voltage-gated Ca2+ channel blocker. EC50 and pA2 values are 1.4 nM and 10.3 for relaxation of depolarization- and Ca2+-induced contractions of rabbit aorta respectively; EC25 = 0.45 nM for reduction in rate of spontaneously beating guinea pig right atria. Long-acting antihypertensive agent in vivo, exerting primary effects on vascular tissue with secondary negative chronotropic action.