Coping with toxic overdose

The most common significant cardiotoxic overdoses involve non-dihydropyridine calcium channel blockers and beta-blockers. In this video, from our ICU Masterclass: Inotropes and Vasopressors course, we'll cover the mechanisms of toxicity and how specific agents can be used to revive patients who have overdosed on these medications.

Providing hemodynamic support for unstable patients can be a daunting process. In our ICU Masterclass: Inotropes and Vasopressors course, you’ll learn a systematic, hands-on approach for using vasopressors and inotropes. You’ll discover why one size does not fit all, as well as the underlying mechanisms of action of these agents, so that you can safely and effectively use the appropriate agent for each unique patient.

Common cardiotoxic drugs

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The pathway for myocyte contraction may be interrupted in several places. The most common significant cardiotoxic overdoses are non-dihydropyridine calcium channel blockers and beta-blockers. 

Calcium channel blockers toxicity

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Calcium channel blockers like diltiazem and verapamil interrupt the influx of calcium at the cell membrane, which can decrease heart rate and the strength of contraction.

Treating calcium channel blocker overdose

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This may be mitigated by aggressive calcium administration. In addition, glucagon may help create an alternate pathway for myocyte contraction. Epinephrine, or other inotropes or vasopressors, may be considered as adjunctive therapies as well. For refractory cases, high dose insulin and glucose infusion or intravenous lipid emulsion may be considered, and ultimately, mechanical circulatory support may be considered for recoverable cases.

Beta-blockers toxicity

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Beta-blockers on the myocyte block the influx of calcium through the calcium channel, but also block the increase in intracellular cyclic AMP.

Treating beta-blocker overdose

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Again, this may be bypassed with the use of glucagon, and calcium supplementation may be helpful in overdose. Beta agonists like dobutamine, isoproterenol, or epinephrine may help offset the receptor blocking effect. High dose insulin and glucose, lipid emulsion, or mechanical circulatory support are again considered for refractory cases.