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Calcium channel blockers (CCB), calcium channel antagonists or calcium antagonists [2] are a group of medications that disrupt the movement of calcium (Ca 2+ ) through calcium channels . [ 3 ] Calcium channel blockers are used as antihypertensive drugs , i.e., as medications to decrease blood pressure in patients with hypertension .
Non-dihydropyridine calcium channel blockers such as verapamil block the slow inward calcium current in cardiac tissues, thereby having a negatively dromotropic, chronotropic and inotropic effect. [5] This (and other) pharmacological effect makes these drugs useful in the treatment of angina pectoris.
L-type calcium channel blockers are used to treat hypertension. In most areas of the body, depolarization is mediated by sodium influx into a cell; changing the calcium permeability has little effect on action potentials. However, in many smooth muscle tissues, depolarization is mediated primarily by calcium influx into the cell.
ATC code C08 Calcium channel blockers is a therapeutic subgroup of the Anatomical Therapeutic Chemical Classification System, a system of alphanumeric codes developed by the World Health Organization (WHO) for the classification of drugs and other medical products. [1] [2] [3] Subgroup C08 is part of the anatomical group C Cardiovascular system ...
Class IV agents are slow non-dihydropyridine calcium channel blockers. They decrease conduction through the AV node , and shorten phase two (the plateau) of the cardiac action potential . They thus reduce the contractility of the heart, so may be inappropriate in heart failure.
It is a potent and mild vasodilator of coronary and peripheral vessels, respectively, [29] which reduces peripheral resistance and afterload, though not as potent as the dihydropyridine (DHP) calcium channel blockers. This results in minimal reflexive sympathetic changes. [citation needed]
Class III antiarrhymics act as potassium channel blockers, while Class IV antiarrhymics are non-dihydropyridine calcium channel blockers. While the effects of these drugs may be antiarrhymic, they can also be proarrhymic in other contexts.
In cardiac pharmacology, calcium channel blockers are considered class-IV antiarrhythmic agents. Since calcium channels are especially concentrated in the sinoatrial and atrioventricular nodes , these agents can be used to decrease impulse conduction through the AV node, thus protecting the ventricles from atrial tachyarrhythmias .