Hyperglycemia associated with propranolol and chlorpropamide coadministration

A 59-year-old patient with acute pancreatitis is described, whose treatment was complicated by concomitant diabetes mellitus and arterial hypertension. He received propranolol and insulin without subsequent problems; however, when the insulin was changed to chlorpropamide, a significant increase in blood sugar occurred. It was postulated that this increase in blood sugar was due to an antagonistic action of propranolol at the pancreatic level which interfered with the action of chlorpropamide.