Pharmacodynamics of amlodipine: hemodynamic effects and antianginal efficacy after atrial pacing.

The hemodynamic effects and antianginal efficacy of 10 mg amlodipine administered intravenously were assessed for 45 minutes in 18 subjects with stable angina pectoris. After amlodipine the heart rate was increased from 75 +/- 12 beats/min to 80 +/- 15 beats/min (p less than 0.05) for at least 15 minutes, with a decrease in systemic vascular resistance of 1091 +/- 205 to 815 +/- 390 dynes/sec/cm5 and a decrease in mean arterial pressure at 30 minutes from 99 +/- 11 to 91 +/- 10 (p less than 0.05). There was no change in dp/dt or dp/dt/IP or in cardiac output, wedge pressure, or pulmonary artery pressure. In the parallel placebo group (n = 8) there was no change in any of the hemodynamic parameters. Time to pacing-induced angina was increased in the treated group (n = 12) from 6 +/- 3.2 minutes before the dose to 8.2 +/- 4 minutes after the dose (p less than 0.01) compared to the control subjects who were given saline solution, in whom the time increased from 7 +/- 1.5 minutes before the dose to 7.5 +/- 2.2 minutes after the dose (n = 9). The double product at an equivalent pacing time to the initial onset of angina was reduced after therapy from 15,590 +/- 1490 to 14,100 +/- 1193 with a reduction in ST segment shift from 11.9 +/- 9.4 mm2 to 6.2 +/- 5.6 mm2 (p less than 0.05). Amlodipine after intravenous use has a vasodilator effect and also increases the anginal threshold without deleterious negative inotropic effects.