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Acute responses to urapidil in hypertensive persons
P W de Leeuw1, W H Birkenhäger
1Department of Medicine, Zuiderziekenhuis, Rotterdam, The Netherlands.
The American Journal of Cardiology
|August 15, 1989
Summary
Urapidil effectively lowers blood pressure by reducing renal vascular tone and increasing renal perfusion. This antihypertensive agent stimulates sympathetic systems and mildly activates the renin-angiotensin system, with increased aldosterone possibly linked to decreased dopamine.
Area of Science:
- Cardiovascular Pharmacology
- Nephrology
- Hypertension Research
Background:
- Urapidil is an antihypertensive agent with dual peripheral and central mechanisms.
- Essential hypertension requires evaluation of drug effects on renal hemodynamics and pressor systems.
Purpose of the Study:
- To assess the acute effects of intravenous urapidil on renal vascular tone and pressor systems in hypertensive patients.
- To compare urapidil's impact against a placebo in a randomized crossover design.
Main Methods:
- A randomized, placebo-controlled, crossover study involving 10 patients with essential hypertension.
- Intravenous administration of urapidil (25 or 50 mg) or placebo, with measurements of blood pressure, heart rate, renal plasma flow, plasma renin concentration, angiotensin II, aldosterone, and catecholamines.
Main Results:
- Urapidil significantly reduced blood pressure and renal vascular tone, while increasing heart rate and renal blood flow.
- Plasma levels of noradrenaline and adrenaline increased, dopamine levels decreased, and aldosterone significantly increased.
- Renin and angiotensin II showed only mild stimulation.
Conclusions:
- Intravenous urapidil provides an immediate blood pressure-lowering effect with improved renal perfusion.
- The drug stimulates sympathetic and, to a lesser extent, renin-angiotensin systems.
- Elevated aldosterone may be partly attributed to suppressed dopamine levels.