Efficacy of trimazosin and prazosin therapy on cardiac and exercise performance in outpatients with chronic congestive heart failure.

The effect of trimazosin versus placebo therapy in 16 patients and of prazosin versus placebo therapy in six patients on treadmill exercise performance was evaluated in two double-blind, randomized studies in patients with chronic left ventricular failure despite therapy with digitalis and diuretics. The administration of trimazosin and prazosin was effective in lowering resting systolic and diastolic blood pressures and resting heart rate times systolic blood pressure, and the administration of trimazosin was effective in decreasing exercise diastolic blood pressure. Trimazosin and prazosin therapy was also effective in diminishing clinical symptoms, in lessening roentgenographic evidence of pulmonary venous congestion and in improving exercise duration until marked dyspnea. Based on these data, we conclude that the vasodilators, trimazosin and prazosin, are effective in treating chronic left ventricular failure.