[Prazosin long-term treatment in severe chronic cardiac failure (author's transl)]

In addition to digitalis and diuretics, 10 patients with chronic cardiac failure were treated with prazosin (15 mg/d) over a period of 6 months. It was shown that the mean pulmonary artery pressure decreased significantly, on average by 30%, during both rest and exercise. Despite significant decrease of arterio-central venous oxygen difference no improvement of cardiac output was measured after 6 months on prazosin. Cardiac output increased clearly in only 4 patients, particularly during exercise. Heart rate and arterial blood pressure remained statistically unchanged. Eight patients reported subjective improvement of dyspnoea after 6 months. Prazosin plasma levels were between 9.4 and 58.6 ng/ml. Side effects such as orthostatic hypotension, urinary incontinence and disturbances of potency occurred in 4 patients. Antinuclear factors could not be demonstrated after 6 months. These data show that after 6 months of prazosin therapy haemodynamically significant improvement of pulmonary congestion can be demonstrated without concurrent increase of cardiac output. Prazosin is indicated in treatment of chronic cardiac insufficiency with predominant pulmonary congestion an an adjunct to digitalis and diuretic baseline treatment.