Hemodynamic differences between metoprolol and carvedilol in hypertensive patients.

Resting hemodynamics were measured before, at 2 and 24 h after the first dose, and after 4 weeks of monotherapy with either metoprolol or carvedilol in a randomized single-blind study. We analyzed results from 24 hypertensive patients (30-68 years of age) with adequate blood-pressure lowering on monotherapy. Acutely, both drugs lowered systolic blood pressure and heart rate. Whereas metoprolol reduced cardiac output and increased both systemic and femoral artery resistance, carvedilol did not alter cardiac output but led to reductions in the systemic and regional resistances. After 4 weeks of therapy, cardiac output remained reduced and vascular resistances increased in the metoprolol group, whereas in carvedilol patients cardiac output continued to be unchanged and the trend for vascular resistances to be decreased persisted. Acutely and chronically the differences in the hemodynamic effects of the two medications were statistically significant. The study results indicate that carvedilol's vasodilatory action is not subject to tolerance development. Chronic afterload reduction associated with the decrease in systemic vascular resistance may lead to additional savings in myocardial oxygen consumption, a beneficial feature particularly in those patients with concomitant ischemic heart disease. It may also have a favorable influence on concentric cardiac hypertrophy and changes in the walls of arteriolar resistance vessels.