Calcium Channel Blockers (Mechanism of Action)
๐ Calcium channel blockers (CCBs) are used in the treatment of many cardiovascular conditions including hypertension and angina. They are divided into subclasses, non-dihydropyridines, and dihydropyridines and differ by their pharmacokinetic properties, clinical uses, response, and selectivity. โ
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๐ The name of this class, calcium channel blockers, hints at its mechanism of action โ inhibits the entry of calcium into cells of the cardiac and peripheral vascular smooth muscles. โ
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๐๏ธ Calcium entry into L-type channels of cardiac and peripheral vascular cells is needed for them to contract or constrict more strongly. โ
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๐๏ธ By blocking calcium entry, calcium channel blockers cause:โ
๐๐ป peripheral vascular smooth muscle relaxation (decreases blood pressure)โ
๐๐ป decreased myocardial contractility (decrease myocardial demand making them effective in angina)โ
๐๐ป decrease heart rate and conduction velocity (useful in arrhythmias). โ
