An evaluation of the safety of the β‐modulator cicloprolol in chronic heart failure

The new beta-adrenoceptor partial agonist cicloprolol acts as a beta-agonist at normal levels and as a beta-antagonist at high levels of adrenergic discharge. Treatment with cicloprolol should protect the heart against excessive stimulation, while providing a baseline level of sympathetic drive. The clinical interest of such a profile is, however, not yet established in heart failure. Accordingly this study examined the safety of oral cicloprolol, a step necessary before undertaking efficacy comparison with other compounds recently proposed to treat heart failure. Twenty-five patients were studied. Cicloprolol was given once a day for 2 weeks in a crossover double-blind placebo-controlled design. Follow-ups were obtained at baseline and at the end of each period. At baseline all patients had clear evidence of heart failure. Cicloprolol did not affect resting heart rate and blood pressure, but it reduced significantly peak exercise heart rate and peak rate-pressure product. The effect was especially significant in patients with sinus rhythm. The drug did not induce bradycardia or arrhythmias. Resting and exercise ejection rate were not affected. Cicloprolol improved the quality of life and the work capacity of 5 of 12 patients with congestive failure due to ischemic etiology. Side effects were few and similar with placebo and cicloprolol. Thus, short-term administration of cicloprolol is safe in moderate heart failure.