Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antihypertensive effects of urapidil and clonidine have been studied in a double-blind cross-over trial in 11 hypertensive outpatients with mild to moderate hypertension, at rest and during isometric exercise. Urapidil 30 mg b.i.d. significantly decreased the standing diastolic blood pressure (p less than 0.05) and the systolic blood pressure at the end of isometric exercise (p less than 0.05). Clonidine 0.075-0.15 mg b.i.d. was more effective in decreasing both systolic and diastolic blood pressure in the supine and standing positions as well as during isometric work (p less than 0.05-0.001). Urapidil caused fewer side-effects than clonidine. Overall, in the doses used urapidil had a weaker antihypertensive effect and caused fewer side-effects than clonidine.
 ...
PMID:Antihypertensive effects of urapidil and clonidine: a double-blind cross-over study. 388

To test the hypothesis that the hypotensive action of urapidil is in part related to a direct action on the brain, the central (intracerebroventricular) and peripheral (intravenous) effects of urapidil were studied and compared with those obtained with clonidine and prazosin. All studies were conducted in conscious, chronically instrumented stroke-prone spontaneously hypertensive rats (SHRSP). Efferent sympathetic nervous system activity was estimated by means of a bipolar electrode implanted on the splanchnic nerve. Only clonidine, administered intracerebroventricularly and intravenously, decreased sympathetic nerve activity. Urapidil and prazosin either did not affect sympathetic nerve activity after central administration or increased it after peripheral administration at low and high doses, respectively. Centrally administered urapidil and prazosin lowered blood pressure but also blocked the response to intravenously administered phenylephrine; this result suggests a peripheral effect. Centrally administered urapidil decreased heart rate. Urapidil given either intracerebroventricularly or into the cisterna magna had no influence on baroreceptor responses. Intravenous infusions of urapidil and prazosin in sufficient doses to lower blood pressure in spontaneously hypertensive rats by 50 mm Hg completely blocked the actions of phenylephrine. These data suggest that in conscious SHRSP urapidil lowers blood pressure through peripheral blockade of alpha 1-adrenergic receptors rather than by means of central sympathetic suppression. In this regard urapidil resembles prazosin rather than clonidine; however, the effect of urapidil on heart rate is consistent with a central mode of action.
Hypertension 1986 Apr
PMID:Effect of urapidil, clonidine, and prazosin on sympathetic tone in conscious rats. 395 16

Urapidil (Ebrantil) is a new antihypertensive agent exerting central and peripheral action which is recognized for the treatment of both chronic and acute hypertension. The purpose of the present study was to investigate the extent of the antihypertensive effect of urapidil in various forms of general or regional anaesthesia. To this end, a retrospective analysis was first carried out on the typical reactions of the circulatory system in 200 patients during either neuroleptanalgesia with diazepam and droperidol, or halothane, enflurane or intrathecal local anaesthesia. In a prospective study, each of 5 normo- or hypertensive patients undergoing elective surgery with one of the aforementioned anaesthetic procedures received 50 mg urapidil intravenously 25-30 min after start of anaesthesia. Blood pressure and heart rate measurements were performed for up to 24 h after the injection. Whereas anaesthesia alone caused a moderate drop in systolic and diastolic blood pressure of 3.1 and 2.1%, respectively (in normotensive patients), and of 12.0 and 6.7%, respectively (in hypertensive patients), urapidil caused a further significant fall in blood pressure in the hypertensive patients within a few minutes, but not in the normotensive groups. This effect was particularly pronounced under spinal anaesthesia and usually persisted until the end of the operation. Heart rate was (not significantly) increased for a few minutes after administration of urapidil. Temporary blood pressure reduction to hypotensive values was observed in 2 of the 50 patients only. From the results it is concluded that urapidil is an effective and relatively safe drug for the treatment of elevated blood pressure during routine surgery. Even if it has been administered on the basis of wrong indication (e.g. hypertensive phases as a result of insufficient anaesthesia), it rarely will cause blood pressure to fall to undesired low levels after anaesthesia has been normalized.
 ...
PMID:[Circulatory changes with urapidil (Ebrantil) in general and regional anesthesia. Studies with normo- and hypertensive patients]. 408 65

In conscious instrumented normotensive and two-kidney, one clip Goldblatt hypertensive dogs, we compared the effects of the alpha-receptor blocking agent, urapidil, on blood pressure, renal vascular resistance, heart rate, and plasma renin activity with those of prazosin and phentolamine. Urapidil (2 mg/kg) and prazosin (0.25 mg/kg) decreased blood pressure and renal vascular resistance in both groups of animals, and urapidil caused a small increase in renal blood flow. Heart rate, but not plasma renin activity, was increased at the peak of the hypotension. Phentolamine had no significant effect on any of these parameters. All three agents markedly inhibited the renal vasoconstrictor responses to intraarterially administered phenylephrine and norepinephrine, and thus exhibited an alpha 1-receptor blocking action. Only urapidil significantly antagonized the response to B-HT 933, a selective alpha 2-receptor agonist, indicating that it also interacts at alpha 2-receptor sites. Since both normotensive and hypertensive animals exhibited similar hypotensive responses after both urapidil and prazosin, the degree of alpha-receptor blockade achieved did not reveal greater sympathetic tone in renal hypertension.
Hypertension
PMID:Relationship of alpha receptor types to hypotension and renal vasodilation caused by alpha blockers in conscious dogs. 613 Oct 31

The influence of urapidil, an arylpiperazinederivate, on intracranial pressure (ICP), mean arterial pressure (MAP) and cerebral perfusion pressure (CPP) was investigated in dogs with (group II) and without (group I) intracranial hypertension. After i.v. administration of urapidil, intracranial pressure remained unchanged and cerebral perfusion pressure decreased to the same extent as mean arterial pressure (20%). As in neurosurgical patients, autoregulation of cerebral blood flow is often lost; a sudden increase in blood pressure may lead to an increase in cerebral blood flow and to a damage of the blood bain barrier with consequent cerebral edema. Urapidil seems to be suitable for treating hypertensive episodes perioperatively in neurosurgical patients.
 ...
PMID:The influence of urapidil, a new antihypertensive agent, on cerebral perfusion pressure in dogs with and without intracranial hypertension. 686 21

The vasodilating effect of 6-(3-[4-(o-methoxy-phenyl)-piperazin-1-yl]-propylamino)-1,3-dimethyluracil (urapidil, Ebrantil) and phentolamine was investigated during extracorporeal circulation in patients undergoing coronary artery bypass (CABG) operations. To compare the vasodilating effect, 10 patients received 2 times 25 mg urapidil, and another 10 patients 2 times 5 mg phentolamine when mean arterial blood pressure (MAP) exceeded 100 mgHg. Both drugs caused a significant (p less than 0.01) decrease in mean arterial blood pressure and total peripheral resistance (TPR), using constant flow (Qecc). Central venous pressure (CVP), measured in the inferior vena cava, showed no significant change, while a marked volume loss (delta V) in the oxygenator was observed. There was no significant difference in the measured cardiovascular parameters in the two groups of patients. The peripheral vasodilating effect of urapidil, expressed in mg was found 5 times weaker than that of phentolamine. Urapidil was found effective in the treatment of hypertension during extracorporeal circulation.
 ...
PMID:Control of hypertension during cardiopulmonary bypass with urapidil and phentolamine. 719 59

Urapidil is a vasodilator acting on peripheral vessels by alpha-1 adrenoceptor blockade, and on central nervous system by alphaadrenoceptor blockade on the tractus solitarius nuclei and stimulation of serotoninergic receptors. Its hepatic metabolism and central action explain the absence of rebound effect when treatment is stopped. Urapidil is an arterial and venous vasodilator in systemic and pulmonary circulation. Therefore urapidil decreases systemic and pulmonary arterial pressures and left and right ventricular preload. These effects are accompanied by moderate effects on heart rate, and increased cardiac output in patients with heart failure. Some adverse effects observed with other vasodilators are absent (increased intracranial pressure and intrapulmonary shunt, negative inotropic effect, tachycardia). IV urapidil is used to treat systemic arterial hypertension perioperatively and hypertensive emergencies. Moreover urapidil has been administered to treat pulmonary artery hypertension in chronic pulmonary disease. Its haemodynamic effects seem proportional to the basal activity of alpha-adrenoceptors. Therefore, wide individual variations in active doses are observed from 12.5 to 50 mg as i.v. bolus in adults. Thereafter i.v. continuous administration or oral treatment may be necessary, depending on the cause of hypertension.
 ...
PMID:[Role of urapidil in the treatment of acute hypertension]. 767 Oct 60

The possible role of peripheral 5HT1A-receptors in the vasodilation caused by urapidil was studied by means of venous occlusion plethysmography in the forearm vascular bed of healthy volunteers. Urapidil is known to be an alpha 1-adrenoceptor antagonist and an agonist of 5HT1A-receptors. The hemodynamic effects of urapidil were compared with those of flesinoxan, a selective 5HT1A-receptor agonist virtually devoid of alpha 1-adrenoceptor antagonistic activity, and with the selective alpha 1-adrenoceptor antagonist doxazosin, which has no affinity for 5HT1A-receptors. Urapidil, as well as doxazosin, caused a dose-dependent decrease in forearm vascular resistance (FVR), thus reflecting vasodilation. Both urapidil and doxazosin were competitive antagonists of the vasoconstrictor effect of the selective alpha 1-adrenoceptor agonist methoxamine. On a molar base doxazosin proved more potent than urapidil (more than 10-fold). Flesinoxan slightly decreased FVR only at high doses. The nitric oxide (NO)-synthase inhibitor NG-monomethyl-L-arginine acetate (L-NMMA) depressed the vasodilatation caused by serotonin and also that by high-dose flesinoxan. The serotonin-induced vasodilatation is known to be NO-dependent. From the experiments it is concluded that peripheral 5HT1A-receptors cannot play an important role in the vasodilator response caused by urapidil, which is predominantly the result of postsynaptic alpha 1-adrenoceptor blockade. 5HT1A-receptors are clearly not involved in the NO-dependent dilatation caused by serotonin. During chronic treatment of hypertension with urapidil central but not peripheral 5HT1A-receptors may be assumed to play a role.
 ...
PMID:Comparison of the hemodynamic effects of urapidil and flesinoxan in healthy volunteers. 780 8

Hypertension associated with tachycardia, elevated filling pressures and increased systemic vascular resistance occurs in 30-60% of patients recovering from coronary artery surgery (1,2). It is usually present when the patients arrive from the operating room in the intensive care unit (ICU), or develops in the first two hours postoperatively. Traditionally sodium nitroprusside (S) is the drug of first choice for the i.v. treatment and prevention of hypertension and increased filling pressures developing after coronary artery surgery (CAS). Its major disadvantage is reflex tachycardia associated with increased myocardial oxygen consumption. Urapidil (U) has both peripheral alpha-1-adrenoreceptor blocking activity and a central antihypertensive effect at the level of the 5HT-1A serotonergic receptor, resulting in enhanced peripheral sympathetic inhibition (3,4). Informed consent and institutional approval for the study were obtained. When mean arterial blood pressure (MAP) increased above 90 mmHg within the first 2 hours after CAS, 53 patients were randomly allocated to one of two groups. 25 patients received U (bolus of 25 mg; initial infusion rate of 15-85 micrograms/kg/min; maintenance infusion rate of 2-7 micrograms/kg/min) and 28 patients received S (initial infusion rate of 1-2 micrograms/kg/min; maintenance infusion rate of max. 5 micrograms/kg/min). The infusion rate was then adjusted to maintain MAP between 80 and 90. Measuring points were: 1. baseline; 2. 30 min after starting the infusion; 3. 60 min after starting the infusion; and at 2 hour intervals thereafter until the next morning.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Comparison of the effects of urapidil and nitroprusside on hemodynamics and myocardial function in hypertension following cardiac surgery. 780 10

Arterial hypertension is a well known risk factor for atherosclerosis and its complications. Lowering of blood pressure significantly reduces the incidence of cerebrovascular events and to a minor extent that of ischemic heart disease. Interference of antihypertensive drugs on lipoproteins, glucose and electrolytes metabolism has been suggested as a hypothesis for the lower than expected protection against cardiac events. The new antihypertensive agents such as calcium antagonists, angiotensin converting enzyme inhibitors and post-synaptic alpha-1 receptor antagonists have proved to be neutral or to have positive effect on metabolic disturbances. Urapidil, a multifactorial antihypertensive agent, has been shown to significantly lower blood pressure and to have a favorable impact on the metabolic profile in adult and elderly hypertensive patients and in patients with diabetes mellitus and elevated blood pressure. Although arterial hypertension is a risk factor for atherosclerosis, the clinical events at the cerebral and coronary levels are secondary to thrombo-embolic complications. On the other hand it has been shown that abnormalities in coagulation factor has a prognostic value. Therefore, new and old antihypertensive agents should be investigated not only for their effects on hypertension, metabolic profile and quality of life but also on coagulation, in order to improve the therapeutic profile.
 ...
PMID:Modification of cardiovascular risk factors during antihypertensive treatment: current and new approach trends. The urapidil experience. 780 13


<< Previous 1 2 3 4 5 Next >>