Acebutolol, atenolol, and propranolol and metabolic responses to acute hypoglycaemia in diabetics.

In a double-blind crossover study the symptomatic and metabolic effects of propranolol, acebutolol, and atenolol were studied during insulin-induced hypoglycaemia in diabetics treated with diet or hypoglycaemic tablets. All the drugs prevented tachycardia, but did not affect the other symptoms of hypoglycaemia. Propranolol delayed the recovery of the blood glucose concentration and impaired the secondary rise in the concentrations of blood lactate and non-esterified fatty acids in diet-treated diabetics. Acebutolol potentiated the hypoglycaemic effect of insulin in tablet-treated diabetics (mean difference of blood glucose concentration 0.7 mmol/l (12.6 mg/100 ml)) and this difference was maintained during the recovery phase4 the blood lactate response was also impaired. Atenolol did not differ perceptibly from placebo in its effect on the metabolic responses to acute hypoglycaemia. The results may be explained by differences in the known pharmacological actions of these drugs. They support the hypothesis that beta-adrenoreceptor blocking drugs that are highly beta1 specific and without membrane-stabilising activity should be safer than the non-selective drugs when used in diabetic patients at risk from hypoglycaemia.