What are calcium-channel blockers?
Calcium antagonists (blocking drugs-calcium channel L-type, calcium channel blockers slow) - a heterogeneous group of drugs with the same mechanism of action, but differ in several properties, including pharmacokinetics, tissue selectivity, the effect on heart rate.
Classification based on chemical structure:
* Phenylalkylamines (verapamil, gallopamil)
* Benzothiazepines (diltiazem, klentiazem)
* 1,4-dihydropyridines (nifedipine, nitrendipin,
isradipin, nicardipine, nimodipine, amlodipine,
lacidipin, felodipin)
* Difenilpiperaziny (Cinnarizine, flunarizin)
* Diarilaminopropilaminy (bepridil)
From a practical point of view (depending on the influence on the tone of the sympathetic nervous system and heart rate), calcium antagonists (calcium channel blockers) are divided into two subgroups:
* Reflexively increase the heart rate (dihydropyridine derivatives) and
* Reflexively reduce heart rate (verapamil and diltiazem) - for action in many respects similar to beta-blockers.
The main mechanism of action of calcium antagonists (calcium channel blockers) is that they inhibit the penetration of calcium ions from the intercellular space in the muscle cells of the heart and blood vessels through slow calcium channels of L-type. By reducing the concentration of ions Ca2 + in cardiomyocytes and vascular smooth muscle cells, they expand the coronary arteries and peripheral arteries and arterioles, have a pronounced vasodilator action.