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Beta-adrenergic blockade alone does not decrease renal perfusion in black hypertensives
Insights
Beta-adrenergic blockade does not harm renal function in hypertensive patients. This study found pure beta-blockade, without significant blood pressure reduction, did not decrease renal perfusion.
Area of Science:
- Nephrology
- Cardiology
- Pharmacology
Background:
- Essential hypertension is a common condition.
- Beta-adrenergic blockers are widely used antihypertensives.
- Concerns exist regarding their effects on renal hemodynamics.
Purpose of the Study:
- To assess the impact of beta-adrenergic blockade on renal hemodynamics.
- To differentiate effects of pure beta-blockade from those of reduced blood pressure.
Main Methods:
- 18 black patients with essential hypertension were studied.
- Acute and chronic (2 months) administration of atenolol, nadolol, or propranolol.
- Renal hemodynamics were assessed in patients with minimal antihypertensive response.
Main Results:
- Neither acute nor chronic beta-blockade decreased renal perfusion.
- Antihypertensive response was minimal in this patient cohort.
- Pure beta-blockade did not negatively affect renal hemodynamics.
Conclusions:
- Beta-blockade itself does not adversely affect renal function.
- Previous findings of renal impairment are likely due to blood pressure reduction.
- Unopposed alpha-sympathetic vasoconstriction may play a role when blood pressure is lowered.
Abstract:
We assessed the effects on renal haemodynamics in 18 black patients with essential hypertension of acute and chronic beta-adrenergic blockade with three agents having different properties: atenolol, nadolol or propranolol. Six patients received each drug. In our patients the antihypertensive response to beta-blockers was minimal or nonexistent. This permitted us to analyse the effects on renal haemodynamics of 'pure' beta-blockade, as opposed to the combined effects of beta-blockade and decreased systemic perfusion pressure. In this setting, neither acute nor chronic administration (two months) of each of these agents decreased renal perfusion. We conclude, therefore, that beta-blockade per se has no deleterious effect on renal function and previous observations are most probably accounted for by the blood pressure lowering effect of these drugs, either alone or coupled with beta-blockade of the renal vasculature allowing unopposed alpha-sympathetically mediated vasoconstriction.