Concurrent alpha1 adrenergic blockade and angiotensin converting enzyme inhibition in the treatment of congestive heart failure

We tested the hypothesis that concurrent inhibition of the renin angiotensin system by enalapril (5 mg) and the sympathetic nervous system by alpha1 adrenergic blockade (prazosin 1 mg) will be superior to enalapril alone in 17 patients with heart failure on standard therapy, in a single blind, placebo-controlled, randomized parallel group study for 4 weeks. Enalapril alone induced a significant increase in exercise time from 499 ± 412 s to 707 ± 608 s (P < 0.05, ANOVA), but the increase induced by the enalapril + prazosin combination was significantly greater (P < 0.025, MANOVA) from 214 ± 271 to 1007 ± 784 s as was the increase in creatinine clearance (P < 0.05).