Drugs from the group of calcium antagonists are universal - they can be used both in monotherapy and combined treatment - for example with beta-blockers, diuretics or convertase inhibitors.
BLOCKING CHANNELS. CALCIUM CHANNELS
These drugs are also called calcium antagonists or calcium channel blockers - they belong to a diversified group of medicines. However, they are characterized by a common mechanism of action.
Physiological mechanism on whichcalcium channel blockers affect
In muscular cells, including myocardial and muscular arteries - calcium is necessary for strong contraction. The mechanism of action of calcium antagonists is to inhibit the influx of calcium through the calcium channels of cell membranes. Therefore, the use of calcium antagonists is associated with a dose-adjusted dose of weakening of the strength and frequency of myocardial contraction and the arterial muscles.
How do they work?
These drugs inhibit the inflow of calcium ions into the muscle cells of the vascular wall and the heart's cells. In addition, the effect of inhibiting the influx of calcium is also the expansion of peripheral blood vessels and the reduction of the resistance of flowing blood. As a consequence, blood pressure is reduced. The efficacy of calcium antagonists is very highly evaluated in monotherapy of mild and moderate hypertension.
3 groups of calcium antagonists
Due to chemical structure and effects on the circulatory system, calcium antagonists are divided into three groups. The first group includes benzothiazepine derivatives (diltiazem). The second group are derivatives of phenylalkylamines (verapamil). The third group includes dihydropyridine derivatives. The influence of particular groups of calcium antagonists on the circulatory system is diversified.
High-efficacy and selective vasopressives include amlodipine, felodipine, nisoldipine.
Who are they recommended to?
It is believed that this group is particularly effective in hypertensive elderly patients, in patients with coexisting peripheral vascular disease, bronchial asthma and some forms of coronary artery disease. These drugs have a beneficial effect in patients with hypertension and left ventricular hypertrophy, because they cause regression of the latter complication. Calcium channel blockers are readily used in combination with diuretics or convertase inhibitors or beta-blockers. They are also often used in monotherapy of hypertension.
Safety of calcium antagonists treatment
The currently used preparations are almost exclusively of a new generation. They are characterized by the even release of the active substance, during the usually prolonged up to one day's activity. (Usually one tablet a day is enough). The opposite of the current drug safety of the new generation of calcium antagonists - there are threats from the old preparations - with quick and short action. The opinion of the Polish Society of Hypertension is an expression of opinion on this topic: "Currently, in both immediate and chronic treatment of hypertension, the use of calcium antagonists with rapid and short action, especially short-acting nifedipine, is not recommended, which results from their adverse effect on the cardiovascular system. vascular (sudden, unpredictable pressure drop with simultaneous activation of the sympathetic system) that can lead to a heart attack or stroke.
However, slow and long-acting drugs are considered safe and valuable drugs.
They are available in the form of appropriately modified traditional preparations or new drugs with a long half-life.The efficacy and safety of these drugs have been confirmed in many large, multicenter research programs. "
Side effects
Modern currently used calcium channel blockers are drugs well tolerated by patients. The few listed side effects include headache, flushing of the facial skin, swelling around the ankles. Very rare: a feeling of heartbeat, nausea, constipation.
Drug interactions
When using drugs from the group of calcium antagonists should be aware of the possibility of interaction with other drugs. This applies first of all to digoxin, whose concentration under the influence of verapamil may increase up to two times. Therefore, you should rather give up combining these drugs. It is also not recommended to combine calcium antagonists and statins, which may result in an undesirable increase in the concentration of both statins and calcium antagonists in the blood.
Hazardous food interactions with calcium antagonists are also possible.
It is recommended that antagonists of the group of calcium antagonists should give up the consumption of larger amounts of grapefruit juice (or fresh fruit), which is a vegetable flavonoid concentrate. Failure to comply with this recommendation may result in even a several-fold increase in the concentration of a drug from the group of calcium antagonists, which may cause a significant decrease in blood pressure. Similar caution should be exercised using plant preparations containing flavonoids - recommended in the prevention of circulatory diseases, strengthening immunity, etc.
