A Pressor Effect of Nonselective Beta-Blockers in Diabetics with Postural Hypotension

Abstract

Eleven patients with hyperadrenergic diabetic postural hypotension and vagal neuropathy were treated in a double-blind, placebo-controlled study with different beta-agonists and antagonists. A single dose of the beta₂-agonist terbutaline (5 mg) and the beta₁₊₂-agonist orciprenaline (10 mg) did not reduce the fall in systolic pressure on standing up, despite a significant increase in both supine and standing heart rates. The beta₁-antagonist with intrinsic sympathicomimetic activity (ISA) acebutolol (200 mg) and the beta₁-antagonist metoprolol (50 mg) did not influence the fall in systolic pressure either, despite a significant decrease in supine and standing heart rates and disappearance of increase in heart rate on standing up. Only the beta₁₊₂-antagonist propranolol and the beta₁₊₂-antagonist with ISA pindolol (5 mg) could significantly reduce or practically abolish the fall in systolic and diastolic pressure on standing up. This was accompanied by a slight decrease of heart rates and disappearance of difference between supine and standing heart rates, as seen with the other beta-antagonists. Thus, only beta₂-blockade reduced or abolished the fall in systolic pressure on standing up in our patients. These data were confirmed by a three-week crossover trial in 10 of these patients.