Prenalterol as long-term therapy for chronic congestive heart failure. A randomized cross-over trial.

Ten patients with severe chronic congestive heart failure (CHF) due to ischaemic heart disease treated with digitalis and diuretics were randomly allocated to oral treatment with prenalterol (100-200 mg daily in addition to their basal treatment) or to intensified treatment with diuretics in a cross-over trial. A wash-out period of 1-4 weeks was allowed between the two modes of treatment. Most of the patients demonstrated subjective improvement during prenalterol therapy, but this improvement could not be verified objectively by exercise test, echocardiography, chest X-ray or weight measurements. No serious side-effects of either mode of treatment were observed. Heart rate was significantly lower during exercise when the patients were treated with prenalterol than during the control periods or during intensified conventional treatment, indicating that prenalterol acts as a beta-adrenergic receptor blocker during exercise in this patient group. The results indicate that prenalterol is a partial beta-receptor agonist without superior beneficial effects compared to those of intensified conventional treatment in patients with chronic, severe CHF.