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 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the haemodynamic effects of dopexamine hydrochloride, a beta 2-adrenergic agonist with dopaminergic (DA1) activity, in 20 patients with low cardiac output following surgery for coronary artery bypass grafting and/or valve replacement or repair. Following titration of four doses (1, 2, 4 and 6 micrograms.kg-1.min-1), the dose producing the optimal response was infused for up to 48 h (five patients). During the infusion, significant increases in cardiac index and stroke volume were accompanied by significant decreases in systemic vascular resistance. Heart rate increased significantly up to 6 h and thereafter returned to control levels. Mean blood pressure was reduced but did not fall below 60 mmHg. However, in five patients treated for 48 h mean blood pressure had returned to control levels. Unwanted effects (tachycardia and hypotension) were seen chiefly at higher doses, leading us to conclude that infusion rates of 4 micrograms.kg-1.min-1 or less will be useful in the treatment of low cardiac output following cardiac surgery.
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PMID:Haemodynamic effects of different doses of dopexamine hydrochloride in low cardiac output states following cardiac surgery. 135 72

Ibopamine is an orally active derivative of dopamine (DA) which metabolizes to its active form, epinine. Epinine is one of the few catecholamines that possess dopaminergic--DA1 and DA2--activity, alpha 1, alpha 2, beta 1, and beta 2 activity, with indirect sympathomimetic action of dopamine. Ibopamine increased positive dP/dt, stroke volume, aortic blood flow, renal blood flow, and diuresis in animals. In healthy volunteers and patients with heart failure, a single oral dose of ibopamine showed primary vasodilating action (postsynaptic DA1 activity and presynaptic DA2 activity). Following a single oral dose of 100 or 200 mg of ibopamine, the plasma concentration of epinine reached its peak within 30 minutes, and declined rapidly so that concentration was not detectable after 1.5-3 hours. Pharmacokinetics and hemodynamic effects in congestive heart failure patients are also discussed.
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PMID:Clinical pharmacology of ibopamine. 167 50

We have studied the effects of dopexamine and dopamine on systemic and renal haemodynamics in 20 male patients undergoing elective coronary artery bypass surgery. Patients were allocated randomly to two groups (n = 10) who were treated with incremental doses of either dopexamine 1, 2 and 4 micrograms kg-1 min-1, or dopamine 2.5 and 5 micrograms kg-1 min-1, each dose being maintained for 15 min. Measurements were performed before administration of the drug and at the end of the infusion period at each dose. Fentanyl and midazolam were used as anaesthetic agents. Renal blood flow was measured with the argon washin technique. Dopexamine 4 micrograms kg-1 min-1 produced an increase in cardiac index of 117% caused by a 65% reduction in afterload and an increase in heart rate by 61%. Dopamine 5 micrograms kg-1 min-1 caused a 40% increase in cardiac index as a result of an increase in stroke volume. Renal vascular resistance decreased more than systemic vascular resistance with dopamine. With dopexamine, the increase in renal blood flow (66%) was less than the increase in cardiac index, while renal vascular resistance and systemic vascular resistance declined to almost the same extent. The results show that dopexamine exerts systemic and renal effects mainly via stimulation of beta 2-receptors. An action of dopexamine at renal DA1-receptors could not be demonstrated in this study.
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PMID:Cardiovascular and renal haemodynamic effects of dopexamine: comparison with dopamine. 202 87

Dopexamine hydrochloride is a novel compound with properties of DA1-dopaminergic and beta 2-adrenergic receptor agonism and neuronal noradrenaline uptake inhibition. It has been shown to produce beneficial renal and haemodynamic effects in patients with severe heart failure. We compared the haemodynamic effects of dopexamine (0.5 to 6 micrograms/kg/min) with those of dobutamine (5 to 25 micrograms/kg/min) in 9 patients with severe congestive heart failure. The two drugs were similar in their effects at peak infusion rates: heart rate increased (dopexamine 87 +/- 17 to 100 +/- 14; dobutamine 91 +/- 18 to 103 +/- 17 min-1), cardiac index increased (dopexamine 1.7 +/- 0.5 to 2.8 +/- 1.1; dobutamine 1.8 +/- 0.5 to 3.0 +/- 1.1 l.min-1.m-2) and systemic vascular resistance decreased (dopexamine 1553 +/- 221 to 1117 +/- 432; dobutamine 1721 +/- 347 to 1280 +/- 433 dyne.s.cm-5). Neither drug affected pulmonary artery wedge pressure (dopexamine 24 +/- 6 to 22 +/- 6; dobutamine 25 +/- 9 to 24 +/- 10 mm Hg). Dopexamine had significantly lower peak effects on left ventricular stroke work index (dopexamine 20 +/- 9, dobutamine 27 +/- 15 g.m.m-2, P less than 0.05) and cardiac power output (dopexamine 0.71 +/- 0.36, dobutamine 0.93 +/- 0.46 W, P less than 0.05). These haemodynamic effects, due largely to vasodilatation but with some contributory positive inotropy, indicate that dopexamine will be useful in the acute treatment of congestive heart failure.
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PMID:Comparison of the haemodynamic effects of dopexamine and dobutamine in patients with severe congestive heart failure. 201 Feb 43

Fenoldopam mesylate (SK&F 82526-J) is a novel benzazepine derivative. It has selective agonist activity at post-junctional (DA1) vascular dopaminergic receptors, which normally subserve renal artery vasodilation. Previous studies in normal subjects and in patients with hypertension indicate that fenoldopam increases renal blood flow and promotes a sodium diuresis. Drug efficacy was clinically evaluated in eight patients with chronic congestive heart failure (CHF) after a single oral dose of 100 mg of fenoldopam and following 3 days of therapy (100 mg four times daily). Stroke volume index acutely increased from 26 +/- 7 (mean +/- SD) to 30 +/- 4 ml/beat/m2 (p less than 0.05) and left ventricular filling pressure decreased from 26 +/- 13 to 23 +/- 11 mm Hg (p less than 0.05). Systemic vascular resistance decreased from 1513 +/- 159 to 1128 +/- 319 (p less than 0.05). Hemodynamic changes were seen as early as 30 minutes following fenoldopam and returned to control levels by 4 hours. Forearm blood flow, hepatic blood flow, and venous capacitance did not significantly change acutely, but renal blood flow index was significantly reduced (34 +/- 4 to 30 +/- 3 min-1 X 1000, p less than 0.01). Plasma norepinephrine, plasma renin activity, plasma arginine vasopressin, and plasma aldosterone did not significantly change acutely. After 3 days of treatment, 100 mg of fenoldopam again reduced the renal blood flow index (35 +/- 7 to 26 +/- 7 min-1 X 1000, p less than 0.01) and tended to increase plasma renin activity (11.7 +/- 8 to 21.2 +/- 19.4 ng/ml/hr, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hemodynamic, renal, and neurohumoral effects of a selective oral DA1 receptor agonist (fenoldopam) in patients with congestive heart failure. 289 70

Dopexamine hydrochloride (Dopacard) is a new synthetic catecholamine compound, which possesses potent beta 2-adrenergic and DA1-dopaminergic agonistic properties. It is free of alpha-adrenergic activity, has no beta 1-adrenergic activity and is less potent at DA2-dopaminergic receptors than dopamine. In the present study the acute haemodynamic effects of dopexamine hydrochloride were compared to those of dobutamine and nitroprusside in 12 patients with idiopathic congestive cardiomyopathy in an open crossover study. With dopexamine hydrochloride, there were dose-dependent increases from control in cardiac output and stroke volume, decreases in blood pressure, right and left atrial pressure, systemic vascular resistance and pulmonary vascular resistance and little change in heart rate. Similar effects were seen with nitroprusside, apart from a marked increase in heart rate, and with dobutamine, except that systolic aortic blood pressure increased and there was no change in diastolic or mean pressure or pulmonary artery systolic pressure. In general, dopexamine hydrochloride produced effects between those produced by the other two treatments. This suggests that dopexamine with its combined vasodilator and inotropic action has a desirable cardiovascular profile with advantages over the beta 1-receptor agonist dobutamine and the pure vasodilator sodium nitroprusside.
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PMID:Comparison of acute haemodynamic effects of dopexamine hydrochloride, dobutamine and sodium nitroprusside in chronic heart failure. 340 66

Dopexamine hydrochloride is a new intravenous, short-acting agent with agonist activity at beta 2-adrenergic and DA1-dopaminergic receptors. The effects of dopexamine hydrochloride infusion on systemic and coronary hemodynamics, myocardial metabolism and the neuroendocrine system were evaluated in 10 patients with chronic severe congestive heart failure at baseline, at rates of 1, 2, 4 and 6 micrograms/kg/min at 15-minute intervals, and after a 1-hour infusion of the "optimal" dose. Right atrial pressure was reduced by 25% (p less than 0.01), pulmonary capillary wedge pressure by 26% (p less than 0.05), systemic vascular resistance by 44% (p less than 0.001) and pulmonary vascular resistance by 34% (p less than 0.01) after the optimal dose. Heart rate increased by 17% (p less than 0.01), rate-pressure product by 17% (p less than 0.01) and stroke volume index by 31% (p less than 0.001). There was no change in mean arterial pressure, myocardial oxygen consumption, coronary sinus blood flow, myocardial oxygen extraction or norepinephrine balance. None of the patients demonstrated net myocardial lactate production. These findings suggest that dopexamine hydrochloride improves systemic hemodynamics and cardiac performance without adversely affecting myocardial energetics or norepinephrine balance. Thus, dopexamine hydrochloride may be a useful agent for the short-term treatment of congestive heart failure.
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PMID:Dopexamine hydrochloride in chronic congestive heart failure with improved cardiac performance without increased metabolic cost. 340 96

Dopexamine hydrochloride is a new synthetic catecholamine for intravenous use in low cardiac output states with co-existing raised systemic or pulmonary vascular resistance. Dopamine has been commonly used since several years in these situations. The drawbacks of dopamine include a vasoconstrictive effect with high infusion rates, and a marked tendency for ventricular ectopy due to the potent beta-1 adrenergic stimulation. Dopexamine hydrochloride has interesting vasodilator properties, with marked intrinsic agonist activity at beta-2 adrenoreceptors and a lesser agonist activity at dopaminergic receptors (DA1 and DA2). Its mild inotropic activity arises primarily from baroreceptor reflex stimulation with a possible contribution from direct stimulation of myocardial beta 2-adrenoreceptors. Dopexamine hydrochloride is responsible for an inhibition of neuronal re-uptake of catecholamines (uptake-1), producing an indirect stimulation of cardiac beta 1-receptors. This catecholamine has no effect at alpha 1 and alpha 2-adrenoreceptors, and only very weak and clinically insignificant beta 1-adrenoreceptor agonist activity. Dopexamine hydrochloride improves cardiac performance by a marked vasodilation and a mild inotropic activity. The specific activity at dopaminergic receptors increases cerebral, myocardial, splanchnic and renal blood flows. These haemodynamic effects are associated with an increase in diuresis and natriuresis. These benefits are achieved without side effects such as an increased myocardial oxygen consumption, although induced tachycardia may be responsible for chest pain/anginae pain in patients with ischaemic heart disease. In clinical practice, dopexamine hydrochloride is easy to use; the short plasma half-life (6 minutes in healthy volunteers and 11 minutes in patients with low cardiac output) allows a rapid return to pretreatment status at discontinuation of the infusion. Preliminary studies have shown that dopexamine hydrochloride can produce beneficial effects in patients with acute heart failure or with compromised left ventricular function following cardiac surgery. The drug has also been assessed in patients with septic shock, most often in association with dopamine or norepinephrine. In these patients, dopexamine produces a dose-related increase in cardiac index, stroke volume, heart rate and a decrease in systemic vascular resistance. Its use in this indication must be cautious, particularly in patients with hypotension or decreased venous return. Comparative therapeutic trials are clearly required to establish the efficiency and tolerance of dopexamine hydrochloride in comparison with dopamine and dobutamine, before its place in therapy can fully be defined.
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PMID:[Dopexamine: a new dopaminergic agonist]. 790 85

Fenoldopam, a newly developed intravenous dopaminergic DA1 receptor agonist, was used in an open, prospective study for blood pressure control in 12 patients presenting with hypertensive crisis. At a dose of 0.2-0.5 microgram kg-1 min-1 fenoldopam decreased systolic blood pressure from 209 +/- 13 to 151 +/- 17 mmHg and diastolic blood pressure from 114 +/- 10 to 78 +/- 10 mmHg. Blood pressure was controlled in all 12 patients within 5-50 min. In none of the patients did rebound hypertension occur upon termination of the study medication, nor was any adverse event reported. Major hemodynamic changes induced by fenoldopam were a decrease in total peripheral resistance from 1853 +/- 611 to 1193 +/- 368 and in pulmonary vascular resistance from 252 +/- 170 to 180 +/- 74 dyne s-1 cm-5. In patients with high left ventricular filling pressure at study pulmonary capillary wedge pressure decreased while the stroke volume index and mixed venous oxygen saturation increased under fenoldopam. Thus, fenoldopam appears to be a rapid-acting, well-tolerated, and highly effective intravenous substance for the treatment of severe hypertension.
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PMID:Hemodynamic profile of intravenous fenoldopam in patients with hypertensive crisis. 790

In the present studies, the efficacy of dopexamine hydrochloride, a novel DA1-receptor and beta 2-adrenoceptor agonist in preventing deterioration of cardiovascular function in a canine model of hemorrhagic shock was investigated. Pentobarbital-anesthetized dogs were allowed to bleed into a height-regulated reservoir and the hypotensive state (about 40 mmHg) was maintained for a period of 150 min. Subsequently, blood was reinfused and recoveries in various hemodynamic variables were monitored for an additional period of 120 min. Either aqueous solvent or dopexamine HCl was randomly selected for i.v. infusion beginning 30 min before reinfusion of the blood and until the termination of the experiment. In the solvent-treated control group, various cardiovascular variables such as cardiac output, stroke volume, celiac and superior mesenteric arterial blood flows progressively declined to 50% or less of the basal values; these changes were associated with sustained increases in the regional as well as systemic vascular resistances. Dopexamine infusion lowered vascular resistances and facilitated recoveries in various hemodynamic variables to 80% to 100% of the basal values after reinfusion of the shed blood. With the exception of a transient inotropic effect during reinfusion in the dopexamine treated group, there were no essential alterations in the myocardial contractility, during the hypotensive state and/or after reinfusion of the blood. Hence, the results indicate that the efficacy of dopexamine to reduce vascular resistance by actions at DA1-receptors and beta 2-adrenoceptors would account for its ability to improve myocardial performance (secondary to reductions in afterload) and restoration of mesenteric and celiac hemodynamics.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evaluation of the effects of dopexamine, a novel DA1 receptor and beta 2-adrenoceptor agonist, on cardiac function and splanchnic circulation in a canine model of hemorrhagic shock. 809 68


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