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Calcium channel blocker poisoning

Fermin Barrueto, Jr, MD, FACEP, FAAEM, FACMT
Section Editor
Stephen J Traub, MD
Deputy Editor
Jonathan Grayzel, MD, FAAEM


Calcium channel blockers (CCBs) are used in the treatment of hypertension, angina pectoris, cardiac arrhythmias, and other disorders. These medications are available in both immediate-release and extended-release preparations; the latter are in wide clinical use (figure 1) [1].

The potential toxicity of these agents is substantial, and is often under appreciated by the public. As an example, over 9500 cases of CCB intoxication, caused by intentional or unintentional overdosage, were reported to poison centers in the United States during 2002 [2]. Although only 16 percent of all cardiovascular drug exposures were due to CCBs, this class accounted for 38 percent of deaths [2].

The management of CCB intoxication will be reviewed here. A summary table to facilitate emergent management is provided (table 1). An overview of the major side effects of CCBs is presented separately. (See "Major side effects and safety of calcium channel blockers".)


The calcium channel blockers (CCBs) can be divided into two major categories based upon their predominant physiologic effects: the dihydropyridines, which preferentially block the L-type calcium channels in the vasculature; and the nondihydropyridines, such as verapamil and diltiazem, which selectively block L-type calcium channels in the myocardium [1,3].

The L-type calcium channels are responsible for myocardial contractility and vascular smooth muscle contractility; they also affect conducting and pacemaker cells. The dihydropyridines (including nifedipine, amlodipine, felodipine, nicardipine, nisoldipine, isradipine, and lacidipine) are potent vasodilators that have little negative effect upon cardiac contractility or conduction at standard doses. In contrast, verapamil and, to a lesser extent, diltiazem are weak vasodilators but have a depressive effect on cardiac conduction and contractility [3].

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Literature review current through: Nov 2017. | This topic last updated: Feb 22, 2017.
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