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Hemodynamic effects of carvedilol after acute oral administration in hypertensive and normal subjects
1Department of Internal Medicine, Institut National de la Sante et de la Recherche Medicale (INSERM U 337), Broussais Hospital, Paris, France.
Insights
Carvedilol effectively lowers blood pressure in healthy and hypertensive individuals. The 50mg dose of carvedilol dilates forearm arterioles in hypertensive patients, reducing vascular resistance.
Area of Science:
- Cardiovascular Pharmacology
- Vascular Physiology
Background:
- Hypertension is associated with altered forearm hemodynamics.
- Beta-blocking agents with vasodilating properties may improve vascular function.
Purpose of the Study:
- To investigate the effects of carvedilol on forearm hemodynamics in healthy volunteers and hypertensive patients.
- To determine if carvedilol induces arteriolar dilation and reduces vascular resistance in hypertensive subjects.
Main Methods:
- Pulsed Doppler flowmetry was used to measure forearm hemodynamics.
- Nine healthy volunteers and 12 hypertensive patients received carvedilol (25mg or 50mg) or placebo.
- Measurements were taken before and after drug administration.
Main Results:
- Both 25mg and 50mg carvedilol significantly reduced blood pressure in all subjects compared to placebo.
- Only the 50mg dose significantly decreased forearm vascular resistance in hypertensive patients.
- This reduction in resistance was abolished by wrist occlusion, indicating an arteriolar effect.
- Brachial artery diameter remained unchanged, but tangential tension decreased.
Conclusions:
- Carvedilol effectively reduces blood pressure in both normotensive and hypertensive individuals.
- The 50mg dose of carvedilol induces arteriolar dilation in the forearm of hypertensive patients.
- This vasodilation is associated with a reduction in brachial artery tangential tension.
Abstract:
Forearm hemodynamics using pulsed Doppler flowmetry were studied in nine healthy volunteers and 12 patients with mild-to-moderate hypertension before and after acute oral administration of the beta-blocking and vasodilating agent carvedilol. Both the 25- and the 50-mg dose produced a significant blood pressure reduction by comparison with placebo in normotensive and hypertensive subjects. Only the 50-mg dose caused a decrease in forearm vascular resistance in hypertensive subjects. The decrease disappeared after wrist occlusion. Although brachial artery diameter did not change, a significant decrease in tangential tension was observed. This study provides evidence that carvedilol produced arteriolar dilation within the forearm of hypertensive subjects in association with a decrease in brachial artery tangential tension.