Podcast #323: Calcium Channel Toxicity

Author: Jared Scott, M.D.

Educational Pearls:

• Cardiac myocytes and vascular smooth muscle are dependent on an intracellular calcium influx for contraction. Pancreatic beta cells rely on calcium to release insulin.

• Calcium channel blockers will decrease cardiac contractility and heart rate, but will also cause vascular smooth muscle relaxation with a subsequent decrease in systemic vascular resistance.

• Resultant cardiac depression and hypotension.

• Pancreatic beta cells also use calcium to release insulin, so calcium channel blockade can cause hyperglycemia.

• Treatment for calcium channel toxicity include: fluid resuscitation, calcium gluconate, vasopressors, and high dose insulin.

• Dosing for insulin therapy is usually 1-5 Units/kg/hr. Make sure to add dextrose!

References:

Boyer EW, Shannon M. (2001).Treatment of calcium-channel-blocker intoxication with insulin infusion. New England Journal of Medicine. 344:1721.

Proano L, Chiang WK, Wang RY. (1995).Calcium channel blocker overdose. American Journal of Emergency Medicine. 13:444.

St-Onge M, Dubé PA, Gosselin S, et al. (2014). Treatment for calcium channel blocker poisoning: a systematic review. Clinical Toxicology. 52:926.