title: Inotropic, vascular and neuroendocrine effects of dopexamine hydrochloride and comparison with dobutamine.
abstract: Dopexamine hydrochloride is a novel beta 2- and dopaminergic-receptor agonist proposed for intravenous therapy in patients with congestive heart failure. To gain a clearer knowledge of its efficacy relative to other agents, intravenous infusions of dopexamine hydrochloride (4 micrograms/kg/min) and dobutamine (10 micrograms/kg/min) were administered to 10 patients with congestive heart failure (ejection fraction less than 0.4). Both agents increased stroke volume and cardiac indexes to a similar degree, and both decreased systemic vascular resistance, with a trend toward a greater decrease with dopexamine hydrochloride. Although dobutamine had no significant effect on left ventricular systolic pressure, dopexamine hydrochloride caused a decrease from 121 +/- 8 to 110 +/- 7 mm Hg (p less than 0.01). Both dobutamine and dopexamine hydrochloride increased peak rate of left ventricular pressure development (dP/dt), and there was a trend to a greater increase with dobutamine (control 1,043 +/- 102 mm Hg/s; dobutamine 1,340 +/- 142 mm Hg/s; dopexamine hydrochloride 1,213 +/- 120 mm Hg/s, p = 0.067 vs dobutamine). Plasma norepinephrine levels increased only with dopexamine hydrochloride (+49%, p less than 0.05). Plasma renin activity increased with both agents (dobutamine +38%, p less than 0.06; dopexamine hydrochloride +41%, p less than 0.05). Dobutamine and dopexamine hydrochloride, therefore, improve cardiac function by way of both vasodilator and inotropic mechanisms. At the doses administered, dopexamine hydrochloride relies on a greater systemic vasodilator effect than dobutamine to achieve and increase in left ventricular performance. Increased levels of endogenous catecholamines may contribute to the increased inotropic state with dopexamine hydrochloride.
authors.affiliation: San Diego Cardiac Center, Sharp Memorial Hospital, California 92123.
authors.forename: B E
authors.initials: BE
authors.lastname: Jaski
authors.forename: C
authors.initials: C
authors.lastname: Peters
mesh_terms: D001794:Blood Pressure / Q000187:drug effects; D004280:Dobutamine / Q000627:therapeutic use*; D004298:Dopamine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000503:physiopathology; D006333:Heart Failure / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology; D006352:Heart Ventricles; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D009200:Myocardial Contraction / Q000187:drug effects*; D009490:Neurosecretory Systems / Q000187:drug effects*; D009638:Norepinephrine / Q000097:blood; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
chemical_list: C046318:dopexamine; D004280:Dobutamine; D004298:Dopamine; D009638:Norepinephrine