Calcium channel blockers

Calcium channel blockers or calcium antagonists. All calcium antagonists are very powerful peripheral vasodilators and deplete blood pressure, reducing OPS . Preparations of this group have a specific ability to inhibit the penetration of calcium ions into smooth muscle vascular cells and cause relaxation of smooth muscles. This decreases the activity of myofibrillary calcium-activated adenosine triphosphatase (ATP-ase). The inhibition of ATPase reduces the use of energy-rich phosphates in muscle fibers and reduces the absorption of oxygen by the heart. There are several types of calcium channel blockers: non-dihydropyridine – diltiazem and verapamil, which act on the heart muscle and peripheral arterioles; and dihydropyridine: amlodipine, nifedipine, nicardipine, etc., acting mainly on peripheral vessels.

Calcium antagonists are widely used in the treatment of arterial hypertension in patients with diabetes mellitus and coronary artery disease. They do not impair blood glucose, do not adversely affect lipid metabolism. Verapamil (derivative difenilalkilamina) like – blockers, reduce heart rate (HR), reduces the atrioventricular conduction and exerts a negative inotropic effect. Therefore, verapamil is not prescribed to patients with a heart block higher than I degree or left ventricular insufficiency. Acute myocardial infarction, sinus bradycardia, weak sinus rhythm are also contraindications to the appointment of verapamil. Simultaneous appointment – blockers and verapamil in violation of left ventricular function is contraindicated.

On the other hand, dihydropyridine derivatives (nifedipine, nicardipine) have almost no direct effect on the myocardium, although they can sometimes cause reflex tachycardia. This group includes the most powerful vasodilators, for example, nifedipine has a particularly fast antihypertensive effect, reducing blood pressure after 10–15 minutes. after one dose taken inside or under the tongue. This effect allows the use of nifedipine to treat acute cases of hypertension, however, with long-term antihypertensive therapy, these drugs are apparently no more effective than other calcium antagonists. Treatment with nifedipine is contraindicated in acute coronary insufficiency (acute myocardial infarction and unstable tachycardia).

Diltiazem , a derivative of benzothiazepine, acts on the myocardium clearly weaker than verapamil, but stronger than dihydropyridines.

Prolonged dosage forms of calcium antagonists are characterized by a uniform and long-lasting effect, significantly increasing the range of the patient’s physical abilities. With “mute” ischemia, the possibility of round-the-clock protection of the myocardium is created, which helps prevent a number of sudden deaths. In patients with proteinuria associated with hypertension and diabetes, or chronic renal failure, calcium antagonists of the dihydropyridine group are less effective than verapamil or diltiazem. Prolonged drugs verapamil and nifedipine can be prescribed to receive once a day, prolonged drugs diltiazem – twice a day.

If the patient, in addition to hypertension and angina pectoris, has a disease accompanied by bronchospasm, Raynaud’s disease or intermittent claudication, calcium antagonists should be preferred to  -blockers. Calcium channel blockers do not have adverse metabolic effects, but are just as expensive as ACE inhibitors.

local_offerevent_note June 23, 2019

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