[Comparison of the effect of a selective and a nonselective beta receptor blocker on the ischemic ST segment, lung function and stress-induced decrease in blood glucose]

This study was designed to compare the antihypertensive and anti-ischemic effects of the newly developed cardioselective beta-blocking agent, betaxolol, with the non-selective agent, nadolol, both of which have hydrophilic long acting properties, over a period of 48 hours. Additionally, the study was intended to determine whether betaxolol exerts a lesser influence on pulmonary function and whether beta-1- and beta-2-adrenergic blocking agents also induce a decrease in blood glucose levels during standard bicycle ergometry for three to nine minutes, similar to that reported in association with exercise of longer duration and, if so, whether this effect can be circumvented by the use of a selective agent. Ten patients with angiographically documented CAD, stable exercise angina pectoris and reproducible ST-segment depression of at least 1 mm received on day 1, in a single blind fashion, one tablet of placebo, on day 2 and day 7, in a double-blind, randomized and cross-over fashion, 20 mg betaxolol or 80 mg nadolol, respectively. Bicycle ergometry was performed before, four, 24 and 48 hours after drug with fixed work loads, blood glucose determination before and after ergometry four hours after drug and airway resistance and maximal ventilatory capacity studies were carried out five hours after drug administration. As compared with placebo, betaxolol and nadolol led to reductions of ST-segment depression of 65% (p less than 0.01) and 74% (p less than 0.005) at four hours, of 53% (p less than 0.025) and 56% (p less than 0.01) at 24 hours and 41% (p less than 0.05) and 44% (p less than 0.05) at 48 hours.(ABSTRACT TRUNCATED AT 250 WORDS)