Survival following massive overdose of adrenergic blocking agents (acebutolol and labetalol)

Massive overdosage of adrenergic blocking drugs is associated with severe morbidity and a high mortality rate. We report the case of a 24-year-old medical intern who ingested 9.6 g acebutolol, 7.2 g labetalol and 0.625 g trimipramine in an attempted suicide. Blood samples drawn on admission were shown to contain markedly elevated plasma levels of acebutolol and its major metabolite and of labetalol. The patient was deeply comatose on admission. The heart rate was 60 min-1 (sinus rhythm) and the blood pressure was clinically unrecordable. Atropine, isoproterenol and dopamine initially had no effect on either heart rate or blood pressure. Only following the administration of inordinately large doses of isoproterenol and dopamine, together with glucagon was a clinical response obtained. The patient remained haemodynamically dependent on dopamine for 12 h and isoproterenol for 65 h. The total dose of isoproterenol administered was 260 mg, two thirds of this during the first 12 h. The patient left hospital well after 7 days but was readmitted after 26 days because of intestinal obstruction due to ischemic bowel necrosis.