A haemodynamic study of the effects of combined slow-calcium channel blockade (nisoldipine) and beta-blockade (metoprolol) in coronary heart disease.

The interaction of a new slow-calcium blocker (nisoldipine) and the beta-blocker metoprolol was evaluated in 16 patients with stable angina. Haemodynamic parameters were determined in a control rest and exercise period. Patients were then randomised equally to nisoldipine (4-8 micrograms/kg) or metoprolol (10 mg) and the haemodynamics of monotherapy assessed; finally the second drug was administered and the effects of combination determined. At rest nisoldipine reduced systemic blood pressure and vascular resistance (P less than 0.01); heart rate, cardiac and stroke volume indices increased (P less than 0.01) at an unchanged pulmonary artery occluded pressure. Metoprolol alone reduced heart rate (P less than 0.05) and increased the pulmonary artery occluded pressure (P less than 0.05). Combination therapy reduced systemic blood pressure and vascular resistance (P less than 0.01); cardiac index and pulmonary artery occluded pressure increased (P less than 0.01) at an unchanged heart rate. The effect of combination was influenced by the order of administration; an improvement in cardiac performance was particularly evident when nisoldipine was added to metoprolol. The interaction during dynamic exercise was similar to that at rest. Thus these data indicated the haemodynamic safety of concurrent nisoldipine/metoprolol therapy; the addition of nisoldipine to metoprolol appeared to offset in part the cardiodepressant properties of beta-blockade.