An L-type calcium channel blocker (IC50s = 78.8 to 7.1 nM at -80 and -40 mV, respectively, in guinea pig ventricular myocytes); selective for vascular over myocardial tissue (IC50s = 427 and 20,417 nM, respectively); decreases mean arterial pressure in spontaneously hypertensive rats (ED30 = 58 nmol/kg); ultra-short duration of action with a half-life of approximately 0.5 minutes in anesthetized pigs