[Differential therapy with calcium antagonists. Hemodynamic studies using nifedipine, verapamil and diltiazem].

The haemodynamic effects of nifedipine, verapamil and diltiazem were measured and compared in an open randomized parallel investigation on 44 patients with coronary heart disease and compensated myocardial function. Each set of parameters was measured during a control phase and serially after a single dose (nifedipine in retard form, 20 mg; verapamil, 160 mg; diltiazem, 120 mg) over a period of 180 minutes at rest and after a standardized exercise. All three drugs produced a significant fall in systemic arterial pressure of 10-14% and of left-ventricular stroke work of 10-20% from the initial level. The main differences between the three drugs concerned heart rate and stroke volume. Nifedipine produced a significant rise in heart rate, while it fell by 8-10% below the control value after verapamil and diltiazem. On the other hand, verapamil caused a significant fall in stroke-volume index, while after nifedipine and diltiazem it remained unchanged. These results suggest differential therapeutic use of the various calcium antagonists.