Bench-to-bedside review: hyperinsulinaemia/euglycaemia therapy in the management of overdose of calcium-channel blockers.

Hyperinsulinaemia/euglycaemia therapy (HIET) consists of the infusion of high-dose regular insulin (usually 0.5 to 1 IU/kg per hour) combined with glucose to maintain euglycaemia. HIET has been proposed as an adjunctive approach in the management of overdose of calcium-channel blockers (CCBs). Indeed, experimental data and clinical experience, although limited, suggest that it could be superior to conventional pharmacological treatments including calcium salts, adrenaline (epinephrine) or glucagon. This paper reviews the patho-physiological principles underlying HIET. Insulin administration seems to allow the switch of the cell metabolism from fatty acids to carbohydrates that is required in stress conditions, especially in the myocardium and vascular smooth muscle, resulting in an improvement in cardiac contractility and restored peripheral resistances. Studies in experimental verapamil poisoning in dogs have shown that HIET significantly improves metabolism, haemodynamics and survival in comparison with conventional therapies. Clinical experience currently consists only of a few isolated cases or short series in which the administration of HIET substantially improved cardiovascular conditions in life-threatening CCB poisonings, allowing the progressive discontinuation of vasoactive agents. While we await further well-designed clinical trials, some rational recommendations are made about the use of HIET in severe CBB overdose. Although the mechanism of action is less well understood in this condition, some experimental data suggesting a potential benefit of HIET in beta-adrenergic blocker toxicity are discussed; clinical data are currently lacking.