![]() BB/CCB overdose is a really dangerous cardiac poisoning and to say that high-dose insulin works because it helps a stressed-out heart eats the carbs that it wants doesn’t satisfy my simple brain. We’ve all stated some variation of, “We’re not quite sure why high-dose insulin works, but maybe it has to do with…” And while the official story remains, I’ve always found it hand-wavy. This explanation for why high-dose insulin works is given in countless toxicology lectures as we try to explain away a therapy that we don’t understand. ![]() Together, these effects lead to increased inotropy and improved cardiac function in the setting of BB and CCB overdose. By causing local vasodilation, insulin helps deliver fresh blood to the starving muscle. 2 When the heart is working really hard, it needs a lot of fresh blood to deliver oxygen and nutrients in order to help keep it going, but when it’s working too hard, it doesn’t pump effectively. 2 It also causes vasodilation, which is thought to improve local microcirculation of the heart. Insulin promotes glucose uptake and metabolism in the cardiac myocyte, leading to improved cardiac function. We know that cardiac myocytes generally prefer free fatty acids as a metabolic substrate, but when they get stressed, they start to utilize more and more glucose. The “official” explanation for why high-dose insulin works goes like this: True, but the benefits of insulin infusion have nothing to do with correcting hyperglycemia. Wait, you say, CCBs can cause hyperglycemia by blocking the calcium-channels associated with insulin release. So how does high-dose insulin work? It seems like a funny therapy for a poisoning that causes cardiotoxicity, not glucose dysregulation. This is ten times the standard dose of insulin for the treatment of diabetic ketoacidosis and can be titrated up to effect, with doses >20 units/kg/hr reported in the literature. ![]() It is given as a 1 unit/kg bolus followed by a 1 unit/kg/hour infusion. High-dose insulin infusion is the treatment for symptomatic BB and CCB overdose. So what’s a broken heart to do? This is where high-dose insulin steps in to save the day. ![]() No calcium means hypotension and bradycardia.
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