Beta-blockers in hypertensive non-insulin-dependent diabetics: comparison between penbutolol and propranolol on metabolic control and response to insulin-induced hypoglycemia.

In a single blind randomized study the effects of a 4-week administration of propranolol (160 mg/day) and penbutolol (40 mg/day) on metabolic control and insulin-induced hypoglycemia were tested in 8 non-insulin-dependent diabetics with diastolic blood pressure between 95 and 110 mmHg. The recovery from hypoglycemia was not delayed by either drug; hypoglycemic nadir and Conard's K did not change significantly. Symptoms of hypoglycemia were inhibited to a lesser extent and pulse rate decrease was lower after penbutolol vs baseline (65 +/- 2.4 vs 77 +/- 2.4 beats/min, p less than 0.01) than after propranolol vs baseline (61 +/- 1.06 vs 77 +/- 2.4 beats/min p less than 0.001). Both drugs produced similar and significant effects on blood pressure both systolic and diastolic. There were no significant effects on fasting plasma glucose concentration, HbA1c, IRI, urinary C-peptide, triglycerides, total and HDL cholesterol and FFA. IRG decreased after penbutolol vs baseline 60 min after insulin injection (170 +/- 30.8 vs 125 +/- 15.4 pmol/l, p less than 0.05). These results indicate that the use of beta-blockers, in particular penbutolol, for mild to moderate hypertension may be considered the treatment of choice also in non-insulin-dependent diabetics at the therapeutic doses employed.