Can insulin-treated diabetics be given beta-adrenergic blocking drugs?

Lack of awareness of hypoglycaemia leading to loss of consciousness is a serious problem in some insulin-treated diabetics, and beta-blocking drugs may increase this hazard. A prospective study was therefore carried out over eight months to determine the incidence of hypoglycaemic episodes in 50 insulin-treated diabetics taking beta-blockers, as compared with 100 diabetic controls matched for age, sex, and duration of diabetes. The incidence of loss of consciousness from hypoglycaemia was the same in both groups and was unrelated to the dose of beta-blocking drug used. Five patients taking beta-blockers and 10 controls had episodes of unconsciousness, but four of these patients taking beta-blockers had had similar episodes in the two years preceding treatment. It is concluded that beta-blocking drugs are generally safe in insulin-treated diabetics and that hypoglycaemic unconsciousness resulting from their use is rare.