Influence of beta-blocking drugs on glucose metabolism in patients with non-insulin dependent diabetes mellitus

Abstract

Two beta-blocking agents, non-selective propranolol and beta1-selective metoprolol, were investigated with respect to their effects on glucose metabolism in 10 hypertensive patients with non-insulin dependent diabetes mellitus (NIDDM). The patients were treated randomly for two weeks in double-blind cross-over manner with (a) propranolol, (b) metoprolol, and (c) placebo. Propranolol impaired glucose tolerance when compared to placebo. The increase in blood glucose was associated neither with changes in concentrations of serum insulin, plasma glucagon of free fatty acid nor with alterations in peripheral insulin sensitivity as measured by 125I-insulin binding to mononuclear leukocytes. Although metoprolol had no effect on blood glucose, it increased 125I-insulin binding to mononuclear leukocytes. The increase in insulin binding could contribute to blood glucose control during metoprolol treatment. In search for reasons for poor metabolic control in NIDDM, treatment with non-selective beta-blockers should be kept in mind.