Possible significance of the pharmacological differentiation of beta-blockers for therapy of hypertension

Abstract

1 Cardioselective and non-selective beta-blockers affect to a different degree several aspects of the circulatory homeostasis. The evidence available in this regard has been evaluated and the possible clinical importance of these differences has been discussed. 2 Venous return in partly regulated by beta-receptors (possibly of the beta 2 type) in the venous resistance vessels. Differences in blockade of venous return by the two classes of beta-blockers may, therefore, influence the degree of increase in left ventricular size, left ventricular end diastolic BPs and stroke volume during beta-blockade. 3 At the first part of the dose-reponse curve, non-selective beta-blockers seem to block more effectively renin release than cardioselective beta-blockers. 4 The direction and the extent to which beta-blockers 'directly' affect total peripheral resistance (TPR), is determined by the resultant of the degree of decrease in TPR by blockade of renin release and the extent of the increase in TPR by blockade of the beta 2-receptors in the arteriolar wall. 5 The clinical relevance of these differences could be that--especially in the low doses range--non-selective beta-blockers may be more 'safe' in patients with compromised cardiac function and may be more appropriate for the therapy of high renin hypertension than cardioselective blockers, whereas the latter may be more appropriate for the majority of hypertensive patients who have low to normal renin hypertension.