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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Antihypertensive effects resulting from alpha 1-adrenoceptor blockade and stimulation of central nervous 5-HT1A receptors were compared with the effects arising from stimulation of 5-HT1A receptors alone during arterial hypertension. 2. Urapidil and 5-methyl-urapidil were less effective in decreasing arterial blood pressure than the lowest dose of the selective 5-HT1A receptor agonist, flesinoxan. After the higher dose of urapidil, a certain dampening of barareceptor reflex was found which was also seen with flesinoxan. 3. Flesinoxan was the only drug which did not reduce the exercise-induced increase in systolic arterial blood pressure. 4. Stimulation of 5-HT1A receptors alone, which is assumed to occur with flesinoxan, exerted antihypertensive activity only at low doses, without inducing reflex tachycardia at rest. 5. Only the combined effects of alpha 1-adrenoceptor blockade and 5-HT1A receptor stimulation, as assumed to occur with urapidil and 5-methyl-urapidil, lead to both a decrease in arterial blood pressure at rest and during exercise.
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PMID:Influence of alpha 1-adrenoceptor blockade and/or 5-HT1A agonism on blood pressure and heart rate at rest and during exercise in hypertensive dogs. 135 78

The effects of blockade of alpha 1-adrenergic receptors on the mechanical properties of the arterial wall were studied in 10 spontaneously hypertensive rats (SHR) as compared with 10 matched normotensive Wistar-Kyoto (WKY) rats. Ascending aortic pressure and flow were recorded in open-chest anesthetized rats, and the systemic arterial compliance was calculated. Intravenous injection (1 mg/kg) of Urapidil, a selective alpha 1-adrenergic antagonist, induced a significant decrease in arterial pressure (-26%, p less than 0.01 and -37%, p less than 0.001 in WKY rats and SHR, respectively) without significant changes in cardiac output. In control conditions, systemic arterial compliance was lower in SHR (3.29 +/- 1.52 microliters/mm Hg) than in WKY rats (4.35 +/- 1.35 microliters/mm Hg, p less than 0.01). Urapidil injection induced significant increases in systemic arterial compliance values in both strains (p less than 0.001). In another set of experiments (15 WKY rats and 15 SHR), the carotid compliance (microliters/mm Hg) was determined from the arterial volume-pressure relation under control conditions, after local incubation with Urapidil, and after total abolition of the vascular smooth muscle by KCN. In WKY rats, the carotid compliance increased markedly after incubation with Urapidil at doses corresponding to 1 mg/kg (+31%, p less than 0.01). A further increase in the carotid compliance was observed after KCN poisoning (+11%, p less than 0.05). In SHR, incubation with Urapidil at doses corresponding to 2 mg/kg were necessary to induce a significant increase in compliance (+38%). At this dosage, there was no further increase in compliance after KCN poisoning.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1991 Apr
PMID:Effects of alpha 1-blockade on arterial compliance in normotensive and hypertensive rats. 167 63

A laser Doppler measurement of the microcirculatory flow rate was performed in 10 patients with moderate arterial hypertension before the delivery of a 30 mg capsule of Urapidil and 3 hours later. A significant increase in this flow rate was evidenced, thus demonstrating the arteriolar vasodilative action of Urapidil.
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PMID:[Microcirculatory hemodynamic effects of Urapidil (Eupressyl)]. 179 70

The effectiveness of a new alpha-blocking agent with additional mechanism of action was evaluated during intraoperative hypertensive crises. Urapidil was administered both in bolus form and as a continuous infusion in order to compare the two routes of delivery. During the study systolic, diastolic, mean pressure and heart rate were measured, and results were evaluated using statistical methods. The study showed that urapidil clearly possesses a rapid (bolus route) and long-lasting (continuous infusion) hypotensive function. In conclusion, given its efficacy in hypertensive crises and the absence of side-effects in this study. Urapidil may be considered one of the best choices during intraoperative hypertension crises.
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PMID:[Hypertensive emergency during large vessel surgery]. 208 20

Serotonin is a vasoactive amine which is considered to play a pathogenetic role in systemic hypertension on account of the peripharal vasotonic effect of serotonin. The central serotoninergic neurones excitatory influence of the sympathetic tone may, however, be a contributory cause. Urapidil is a selective S1-serotonic receptor-agonist with alpha-blocking effect. This is considered to influence the presynaptic receptors of the serotoninergic neurones and thus to inhibit the excitatory influence on the sympathetic system. It reduces the blood pressure by reducing the peripheral vascular resistance without simultaneous provocation of reflex tachycardia or reduction in the minute volume of the heart. In anaesthesiology, this may be employed for perioperative hypertension. The preparation appears to be particularly useful in neuroanaesthesia as in contrast to other antihypertensive agents, it does not appear to alter the intracranial pressure.
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PMID:[The use of urapidil in anaesthesia. A selective S1A-serotonin receptor antagonist with antihypertensive action]. 218 61

In 10 patients on chronic haemodialysis treatment for terminal renal failure with hypertension urapidil (Ebrantil) was given in one daily dose of 30 mg, usually continuing the previously used antihypertensive drugs. A significant decrease of the systolic and diastolic arterial blood pressure was achieved in most cases. Full therapeutic effect was manifested after several weeks of drug administration. During the treatment no tendency was noted for orthostatic hypotension, and no other side effects were observed. It seems that urapidil may be useful in the treatment of hypertension in dialysed patients. The usefulness of the drug in monotherapy requires further studies.
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PMID:[Urapidil (Ebrantil) use in patients on chronic hemodialysis]. 221 15

Urapidil (URA) is used to treat acute hypertension in patients with coronary artery disease, but the effect of URA on the performance of ischemic myocardium has not yet been investigated. The present study was intended to assess the function of ischemic myocardium following URA administration. In eight anesthetized (piritramide) open-chest dogs systolic contraction (dL) and end-diastolic length (edL) of myocardium supplied by the left descending (LAD) and circumflex (LCA) coronary arteries were measured by sonomicrometry simultaneously with aortic pressure (AoP), left ventricular end-diastolic pressure (LVedP), heart rate (HR), stroke volume (SV), and LAD-flow (QLAD). QLAD was reduced by LAD stenosis to about 50% of control, decreasing dLLAD by 55%. Concomitantly, edLLAD increased by about 9% and LVedP by 22%, whereas AoP decreased by 5%. Then, URA was given i.v. (0.25 + 0.25 + 0.50 + 1.0 mg/kg) in 15-min intervals. Following URA, the performance of the non-ischemic area was not systematically affected, but dLLAD increased by about 50%. This could neither be related to the significant reduction in afterload (AoP: -8%), nor to an increase in preload (LVedP and edLLAD did not change significantly), nor to an improved oxygen supply via the LAD (QLAD even decreased), although an increased collateral flow the LCA could not be excluded. The increase in systolic shortening correlated very closely to a decrease in heart rate (r = -0.92). It is concluded that the improved function of ischemic myocardium following urapidil resulted from a reduced oxygen demand in consequence to the decrease in heart rate.
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PMID:Effect of urapidil on the performance of ischemic myocardium in anesthetized dogs. 238 20

6-[3-[4-(o-Methoxyphenyl)-1-piperazinyl]-propylamino)-1, 3-dimethyluracil (urapidil, Ebrantil) is capable of significantly influencing the excitation processes of the mammalian myocardial cell in a dose-related manner. At a concentration of 10(-3) mol/l urapidil myocardial action potentials of guinea-pig and hypertrophied or nonhypertrophied rat hearts reveal substantial reduction of the maximum upstroke velocity and marked prolongation. All these effects can completely be washed out within 15 min. Decreased isometric peak tension and time to peak tension indicate that high urapidil concentrations exert an additional negative inotropic effect. Experimental blockade of the individual transmembrane ionic fluxes suggests that urapidil affects the cardiac excitation process in an antiarrhythmic-like manner with inhibition of the initial, rapid Na+ inward current; the repolarizing K+ efflux; and probably also the slow Ca++ inward current. 10(-6) mol/l urapidil does not induce any alteration in the electrical behaviour of myocardium. Since this concentration corresponds to the serum concentrations generally reached in oral therapy of hypertension with urapidil, antiarrhythmic side effects should only occur under exceptional conditions like parenteral administration of high dosage or increased myocardial sensitivity.
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PMID:Influence of the alpha-adrenoceptor antagonist urapidil on transmembrane action potentials of mammalian myocardium. 243 7

Urapidil has been approved as sustained-release capsules containing 30, 60 and 90 mg, respectively, and as ampules containing 25 and 50 mg for treatment of all grades of hypertension, in several countries in Europe, South America, as well as in Japan and other Asian regions. In general, the treatment should start with 60 mg twice daily, 1 capsule in the morning and 1 in the evening. This schedule may be adapted according to the therapeutic needs. During the last few years, urapidil has been investigated extensively in comparison with several types of established antihypertensive drugs. Urapidil given orally has been tested in comparative trials against placebo, acebutolol, metoprolol, captopril, nifedipine and nitrendipine with responder rates of 40 to 70%. These responder rates are to be expected for a variety of antihypertensive drugs in monotherapy. Further studies with clonidine, prazosin and alpha-methyldopa showed similar responder rates as established for the other antihypertensive drugs studied. Adverse reactions include dizziness, headache and nausea and occasionally tiredness, orthostatic dysregulation and gastric disorders. These symptoms were transient, mostly occurring during the early phases of therapy and disappearing as treatment continued. Adverse effects are considered to be mainly due to blood pressure reduction. Intravenous comparative trials have been performed with urapidil against placebo, diazoxide and sodium nitroprusside. Adverse effects of parenterally applied urapidil are similar to those observed during oral treatment. Specific contraindications for urapidil are unknown. However, as for other vasodilating drugs, intravenous urapidil should not be administered to patients with stenosis of the aortic isthmus or with aortic valve insufficiency.
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PMID:Overview of clinical trials with urapidil. 266 12

Urapidil is a postsynaptic alpha 1-adrenoceptor antagonist with a pharmacodynamic profile similar to prazosin. Unlike prazosin, however, urapidil also has some central activity which may explain the apparent improved tolerability of urapidil, including the absence of first-dose syncope. In clinical trials urapidil therapy resulted in significant reductions in blood pressure in patients with mild to severe essential hypertension, with little influence on heart rate. It is an effective antihypertensive when administered as monotherapy or in combination with beta-blockers and thiazide diuretics. In the few patients with cardiac dysfunction who have been studied to date, urapidil has improved myocardial oxygen consumption, systemic vascular resistance, left ventricular function, cardiac output and pulmonary capillary wedge pressure; however, further study is needed to assess the full therapeutic potential of urapidil in these patients. Urapidil has also been used successfully in the treatment of hypertensive emergencies, including eclampsia and pre-eclampsia, hypertensive crisis and hypertension occurring during general and cardiac surgery, rapidly lowering blood pressure without altering heart rate. Urapidil does not affect lipid or glucose metabolism, nor does it impair renal function. In addition, urapidil may be beneficial to patients with pulmonary hypertension, in whom it dilates pulmonary vascular beds to a greater extent than systemic vasculature, although therapeutic trials have not examined this effect. The most common adverse effects associated with urapidil therapy are dizziness, nausea, headache, fatigue and palpitations; however, these tend to be mild and transient and usually do not require discontinuation of treatment. Thus, urapidil offers a useful alternative to currently available drugs for the treatment of mild to severe hypertension, either as monotherapy or in combination with other antihypertensive drugs.
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PMID:Urapidil. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in the treatment of hypertension. 269 46


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