Acute hemodynamic effects of terazosin in hypertensive and normotensive patients

Terazosin, a selective alpha 1-adrenergic antagonist, was administered intravenously to 10 patients undergoing cardiac catheterization to determine its short-term hemodynamic effects. Hemodynamic measurements were performed before and 30 minutes after three doses of the drug: 1, 1, and 3 mg. One milligram of terazosin reduced the blood pressure (systolic/diastolic, mean) from a mean of 152.0/86.3, 110.7 mm Hg by -24.3/-9.4, -15.3 mm Hg (p less than 0.05). In the five patients who received 5 mg of the drug, blood pressure declined in a dose-dependent manner by -21.8/-3.8, -11.6 mm Hg after 1 mg, and by -35.8/-14.8, -22.8 mm Hg (p less than 0.05) after all 5 mg of the drug. The changes in blood pressure paralleled the terazosin-induced decrease in systemic resistance. Similar changes were recorded for pulmonary artery and capillary wedge pressures and pulmonary vascular resistance. The greatest hemodynamic response was noted with the first drug dose; succeeding doses had a progressively diminished incremental effect. Cardiac output, heart rate, and maximum left ventricular dp/dt demonstrated little change, whereas left ventricular end-diastolic pressure decreased after all three doses, reaching significance after 2 mg (-3.4 +/- 0.9 mm Hg, p less than 0.05), and left ventricular ejection fraction tended to increase (+5.6% +/- 2.4%, p less than 0.05 after 1 mg) and showed a dose dependence analogous to that of systemic resistance. Although not generally reaching statistical significance, indexes of aortic stiffness and compliance displayed a favorable effect. These data are consistent with terazosin's specific alpha 1-antagonism. Left ventricular performance is improved by afterload reduction, since terazosin demonstrated no direct effect on cardiac contractility.(ABSTRACT TRUNCATED AT 250 WORDS)