Hemodynamic effects of dopexamine hydrochloride infusions of 48 to 72 hours' duration for severe congestive heart...

Dopexamine hydrochloride, a new dopaminergic derivative with potent beta 2-agonist activity, was administered to 10 patients with severe congestive heart failure. Initially, the drug was infused at increasing dosage to achieve a maximal tolerated dose and then titrated to maintain acceptable clinical parameters over the next 48 to 72 hours. Cardiac index increased significantly during the initial titration and at peak effect. Tolerance over the duration of the study was noted in most patients, although further increases in cardiac index could usually be achieved by modest increases in the infusion rate. The peak hemodynamic effect was noted at an average infusion rate of 4.8 micrograms/kg/min. Both stroke volume and stroke work indexes increased during dopexamine hydrochloride infusion in association with decreases in mean arterial, right atrial, mean pulmonary artery and pulmonary capillary wedge pressures, systemic vascular resistance and pulmonary arteriolar resistance. Cardiac output increased by 60% during the infusion and this was out of proportion to the 12% increase in heart rate at peak effect. Most of the increase in cardiac index appeared to be due to the strong vasodilatory profile of the medication producing afterload reduction, with direct inotropic and chronotropic effects contributing to a lesser degree. Drug-related side effects occurred in 4 patients and were easily controlled by down-titration. Dopexamine hydrochloride is an effective and well-tolerated sympathomimetic agent that increases cardiac index while promoting vasodilatation.