High dose insulin is an inodilator, not an antidote in the poisoned patient!

High dose insulin therapy has become an increasingly popular treatment for poisonings over the last two decades. It is often mistakenly considered an antidote for poisonings of multiple drug classes, including beta-blocker and calcium channel blocker overdose. This misconception has encouraged overzealous and, at times, inappropriate use, particularly in patients who have vasoplegic shock following poisonings from drugs such as dihydropyridine calcium channel blockers. High dose insulin is not an antidote, but rather an inodilator. Its relatively slow onset of action, compared to catecholamine-based inotropes, of 15-60 min makes it best suited to second-line therapy for cardiogenic shock in poisonings. It has no role in isolated vasoplegic shock where it may exacerbate toxicity. It should be used concurrently with noradrenaline to counteract insulin-induced vasodilation. High dose insulin has predictable adverse effects of hypoglycaemia and electrolyte disturbances, particularly hypokalaemia, which can persist long beyond cessation.