Search results
Results from the WOW.Com Content Network
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 .
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.
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.
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]
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 .
The 8th Joint National Committee (JNC-8) recommends calcium channel blockers to be a first-line treatment either as monotherapy or in combination with thiazide-type diuretics, ACEis, or ARBs for all patients regardless of age or race. [7] The ratio of CCBs' anti-proteinuria effect, non-dihydropyridine to dihydropyridine was 30 to −2. [13]
Main page; Contents; Current events; Random article; About Wikipedia; Contact us
Compared with certain other L-type calcium channel blockers (for example those of the phenylalkylamine class such as verapamil) that have significant action at the heart, the dihydropyridine calcium channel blockers lower blood pressure mainly by relaxing the smooth muscle of the blood vessel walls. [3]