Glucose tolerance during chronic propranolol treatment.

Chronic diuretic therapy in hypertensive patients may be associated with a reversible deterioration in glucose tolerance. There is evidence to suggest that beta-blocker monotherapy may cause a deterioration in glucose tolerance in patients with non-insulin-dependent diabetes mellitus but little information about the effects of chronic beta-blocker treatment in hypertensive patients with normal glucose metabolism. A prospective evaluation of the effects of propranolol monotherapy on glucose tolerance was performed in 13 nondiabetic hypertensive patients. One patient developed diabetes mellitus after 1 month of treatment. Of 11 patients, 4 had a 30% or greater increase in fasting glucose after 1 year of therapy and a significant increase in fasting, and 2-hour postglucose-load venous plasma glucose occurred in the 9 patients completing 18 months of treatment. Although the biologic significance of these changes is questionable, the development of hyperglycemia in a patient receiving beta blockers could represent a side effect of drug therapy.