[Hypoglycemia caused by overdose of a new anti-arrhythmia agent: cibenzoline. 3 cases]

Severe fasting hypoglycaemia were observed in three patients treated with cibenzoline, a new class I antiarrhythmic drug. Retrospective analysis of electrocardiographic changes and serum level determinations showed that these reactions were contemporaneous with intoxication by overdosage of the drug. None of the patients was taking any other drug known to produce this adverse reaction, and in the absence of any other cause of hypoglycaemia, we concluded that it was related to the administration of cibenzoline. Thus, cibenzoline is yet another class I antiarrhythmic agent producing hypoglycaemia as an adverse reaction. Serum insulin levels measured in two of the three patients during hypoglycaemia were inappropriately high, suggesting that cibenzoline might stimulate insulin secretion.