The agent involved when our poison center is consulted about cases of calcium channel blocker (CCB) poisoning these days is almost invariably amlodipine. Quite often, the clinical team will be reaching for high-dose insulin (HDI) as they call us.

After all, HDI is often considered a universal antidote when it comes to CCB poisonings, able to reverse all aspects of toxicity from these drugs.

That is a serious misconception. Many physicians think HDI’s effects mimic those of norepinephrine, increasing the force of the myocardial squeeze and constricting blood vessels. In other words, they believe HDI is an inotrope and a vasoconstrictor.

This is not correct! HDI is indeed a positive inotrope, but it is not at all a vasoconstrictor. In fact, HDI is a vasodilator.

Being an inotrope and a vasodilator, HDI is more similar to dobutamine than it is to norepinephrine.

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