High dose insulin overcomes the metabolic effects of calcium channel blocker toxicity by increasing glucose uptake by myocardial cells as well as increasing myocardial lactate oxidation. This improves myocardial contractility without an associated increase in oxygen demand. Risks include hypoglycaemia and hypokalaemia however.
Suggested protocol (adapted from 2):
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Bolus of 25g dextrose (50mls of 50% dextrose)
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1 IU/kg of short acting insulin to saturate insulin receptors
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Titrate short acting insulin infusion 0.5-5 IU/kg/hr
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Dextrose 25 g/hr to maintain euglycaemia
Replace potassium if <2.5mmol/L and there is a source of potassium loss.
