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Calcium channel blockers. Calcium channel blockers in the fight against hypertension. See what "Calcium channels" are in other dictionaries

Calcium is an important trace element necessary for the normal and full functioning of the human body. However, in some diseases, it becomes necessary to “slow down” the action of this component. For this, special drugs are used - calcium antagonists.

Calcium is an active participant in the transmission of signals from nerve receptors to intracellular structures that cause cells to tense and contract. One of the reasons for the development of hypertension, according to modern doctors, is a change in the ratio of calcium in cells and in blood plasma. The amount of calcium in the blood plasma is often reduced, and in the cells it is increased. This is fraught with the fact that the cells of the heart and blood vessels react more intensively than required to irritants, hormones and other biologically active components.

Medicines - calcium antagonists, or AK, will help to cope with this problem. This is a group of drugs for hypertension, which differ in chemical composition, but have a common mechanism of action. It consists in the fact that the process of penetration of calcium ions through special calcium channels into the cells of the heart and blood vessels is inhibited.

Action on the human body

Calcium antagonists are considered one of the best medicines among antihypertensive drugs. They do an excellent job with the main task - bringing blood pressure to normal. However, they also have other positive effects on the body:

1. They are able to normalize heart rate indicators, due to which calcium antagonists are used as antiarrhythmic drugs.
2. ACs are prescribed to patients who have had a stroke, as the drugs have a positive effect on the blood flow of the brain, which is especially important in atherosclerosis of the head vessels.
3. They prevent the formation of blood clots, because they cause inhibition of Ca metabolism in the cells, which contributes to the inhibition of platelet aggregation.
4. Calcium antagonists are able to reduce pressure in the pulmonary artery and cause bronchial dilatation. The presence of anti-atherogenic properties makes it possible to use AK not only as antihypertensive drugs.
5. Reduce tension in the myocardium and its contractility. The antispastic action causes the expansion of the coronary arteries, resulting in increased blood circulation in the heart. And this helps to increase the supply of myocardium with oxygen and nutrients.

Indications

The main indications for prescribing AK drugs are:

• hypertension;
• pulmonary hypertension;
• IHD (ischemic heart disease);
• angina;
• disorder of cerebral and peripheral circulation;
• hypertrophic cardiomyopathy;
• chronic diseases of the carotid arteries;
• tachycardia and other abnormalities in the heart rhythm;
• Raynaud's disease;
• AK is also prescribed to prevent headache attacks.

Classification of calcium antagonists

There are many classifications of calcium blockers, which are based on the chemical composition, duration of action of drugs, etc. In 1996, experts proposed a new classification of AK. Calcium blocking drugs were divided into three groups - drugs of the first, second and third generation. Let's consider in more detail.

1. To medicines first generation include: Verapamil, Diltiazem and Nifedipine. These drugs have a strong hypotensive effect, especially Nifedipine, which often limits their effective use. First-generation drugs have low bioavailability, a short period of exposure, and they quite often provoke the development of undesirable effects: they cause headaches, reddening of the skin, and increase heart rate.
2. List of drugs - calcium antagonists second generation wide enough: Benidipine, Isradipine, Manidipine, Nicardipine, Nilvadipine, Nimodipine, Nisoldipine, Nitrendipine, Felodipine. These drugs are more effective, but also have disadvantages: for many, the action is short, the peak concentration is reached at different times, and it is often not possible to determine the effectiveness for patients in advance.
3. AK third generation created taking into account the shortcomings of medicines of previous generations. The list of drugs of the latest generation includes such drugs: Amlodipine, Lacidipine, Lecarnidipine. These drugs have the following advantages: high bioavailability, long half-life from the body, high tissue selectivity.

If we take into account the practical characteristics of drugs, then, depending on the effect of the drugs used on the heart rate and on the tone of the sympathetic nervous system, AKs are divided into two subgroups:

• dihydropyridine preparations- those that reflexively increase heart rate (for example, Nicardipine, Amlodipine, Lacidipine);
• non-dihydropyridine- reduce heart rate (for example, Verapamil, Diltiazem) and are similar in their effects to beta-blockers.

Mode of application

Let's get acquainted with the method of using some drugs.

1. Nifedipine. It is used orally at a dose of 5 to 10 mg after meals 3-4 times during the day, and to stop a hypertensive crisis - 5-10 mg under the tongue.
2. Nifedipine retard(Corinfar retard). It is prescribed 10-20 mg twice a day after meals.
3. Nifedipine GITS(continuous drug). Used at 60 - 90 mg once a day.
4. Felodipine. It is prescribed after meals, 2.5 - 10 mg once a day. The tablets should be swallowed with water and should not be crushed or chewed, but should be taken whole. The dose, if necessary, increases gradually.
5. Amlodipine. It is used after meals, 2.5 - 10 mg once a day. If necessary, increase the dose gradually. The maximum allowable daily dose is 10 mg.
6. Lacidipine. The initial dose for adults is 2 mg per day. If possible, you should take the drug at the same time, preferably in the morning. The full effect develops after 3-4 weeks of regular use.
7. Nisoldipine. At the beginning of treatment, the dosage is 5-10 mg twice a day. According to indications, after 3-4 weeks, it can be increased to 20 mg per dose. The drug is taken with meals in the morning and evening. You can not chew, you need to drink enough water.
8. Gallopamil. It is prescribed 50 mg 2 times a day. It should be taken either during meals or immediately after it, the maximum allowable dose per day is 200 mg.
9. Diltiazem. It is taken 60-90 mg three times a day. Tablets should not be chewed, they should be taken before meals and washed down with plenty of water. The daily maximum dosage is 360 mg (4 times 90 mg).
10. Diltiazem SR. It is used from one to two times during the day, 120 - 180 mg during meals.

Use during pregnancy and lactation

It is undesirable to take calcium antagonist drugs during pregnancy and breastfeeding, since studies that would be strictly controlled have not been conducted for this group of patients. It is worth considering that some drugs can penetrate both into breast milk and through the placenta. When administered intravenously, the mother may develop hypotension, which causes fetal distress.

However, in some cases, the potential benefit of using calcium antagonist drugs for the treatment of pregnant women may be justified. The decision on treatment is made by the attending physician, taking into account both the condition of the mother and the characteristics of the course of pregnancy.

Contraindications

For all calcium antagonist drugs, the following contraindications for use are defined:

• low blood pressure;
• often the period of gestation (with the exception of Verapamil, Nifedipine);
• heart failure with reduced functionality of the left ventricle of the heart.

Side effects

The most common side effects that develop when taking AK are:

• flushing of the skin of the face;
• a sharp drop in blood pressure;
• swelling of the limbs;
• decrease in systolic activity of the left ventricle.

Dihydropyridine drugs can provoke the development of the following adverse reactions:

• reflex tachycardia;
• peripheral edema;
• gum hypertrophy;
• migraine;
• flushing of the skin of the face.

Non-dihydropyridine calcium antagonists can cause:

• violation of sinus rhythm;
• decrease in automatism of the sinus node;
• atrioventricular conduction disorder;
• stool problems, hepatotoxicity (Verapamil).

Calcium antagonists are effective drugs that are successfully used to treat diseases of the heart and blood vessels. To obtain the maximum benefit from the use of drugs, it is necessary to systematically monitor blood pressure, heart rate, AV conduction, and it is also important to control the presence and severity of heart failure. An important point is the implementation of the doctor's recommendations, and it should also be remembered that self-medication is unacceptable.

Calcium antagonists are a group of drugs that have visible differences in chemical structure and an identical mechanism of action.

They are used to downgrade.

The process of influence on the body is as follows: there is an instant inhibition of the penetration of calcium ions into the cells of the heart muscle, as well as arteries, veins and capillaries through the corresponding tubules. At the moment, the imbalance of this substance in the structures of the body and blood is considered one of the main ones.

Calcium is actively involved in redirecting signals from nerves to intracellular structures that push the smallest units of life to contract. At elevated pressure, the concentration of the substance in question is extremely low, but in cells, on the contrary, it is high.

As a result, the heart muscle and blood vessels demonstrate a vivid reaction to the influence of hormones and others. So what are calcium antagonists and what are they for?

In terms of percentage, this substance ranks fifth among all the mineral components present in the body. Approximately 2% of the body weight of an adult falls on him. It is needed for the strength and health of the bone tissue that makes up the skeleton.

The main source of calcium is milk and derived products from it.

Despite some well-known facts, it is also needed for other processes occurring in every organism. Everyone knows that calcium occupies the first place in the list of essential substances necessary for the normal development of bones and teeth.

It is especially needed for newborns, children and adolescents, since their body is at an early stage of development. However, it is also essential for people of all ages. It is important that they are provided with a daily dose of this essential mineral every day.

If in young years calcium is needed for the proper formation of the skeleton and teeth, then when the body gradually wears out, it acquires a completely different purpose - maintaining the strength and elasticity of the bones.

Another category of people who need it in sufficient quantities are women who are expecting a baby. This is because the fetus must receive its portion of this mineral from the mother's body.

Calcium is essential for maintaining the normal functioning of the heart muscle. He takes an active part in her work, and also helps to regulate the heartbeat. It is for this reason that it is important for every living organism to receive the correct amount of this chemical element.

With high blood pressure, they should be used. They are prescribed only by the attending physician on the basis of a cardiological examination and special tests.

Since the heart is an organ that is responsible for supplying all parts of the body with blood, all systems of the body will suffer if it works poorly. It should also be noted that the mineral is used by the human body in order to set the muscles in motion.

With its deficiency, the performance of the muscles will deteriorate sharply. Blood pressure depends on the beating of the heart, and calcium lowers its level. That is why it is advisable to start taking this irreplaceable substance.

As for the nervous system, the mineral plays an important role in its proper operation without failures and disturbances.

It nourishes its endings and helps to carry out impulses. If there is a deficiency of this substance in the body, then the nerves will begin to use the untouchable strategic reserves that provide bone density.

Excess calcium

First you need to familiarize yourself with the main signs of the accumulation of excessive amounts of calcium:

• complete lack of appetite;
• constipation, flatulence;
• heart palpitations and disruption of the heart;
• the appearance of diseases associated with the excretory organs, in particular, with the kidneys;
• rapid deterioration of a previously stable mental state up to the appearance of hallucinations;
• weakness, drowsiness, fatigue.

An excess of this substance is associated with the problem of D intake into the body. That is why all of the above symptoms do not always indicate that there are disorders in the absorption of only one calcium in the body.

An excessive amount of calcium can manifest itself as a side effect that occurs while taking certain medications in the treatment of intestinal or stomach ulcers, as well as during. This should not be forgotten.

Pronounced symptoms of this phenomenon are not observed immediately and not at all. The starting point of this process is the prolonged and excessive consumption of organic dairy products. In addition, an increased concentration of this mineral is diagnosed in the presence of malignant tumors of the respiratory system, mammary glands, and prostate in men.

Classification of calcium antagonists

Calcium antagonist preparations are divided into several types depending on the chemical structure:

• phenylalkylamine derivatives(, Anipamil, Devapamil, Tiapamil, Tiropamil);
• benzothiazepine derivatives(Diltiazem, Klentiazem);
• dihydropyridine derivatives(, Barnidipine, Isradipin, Felodipine, etc.).

Dihydropyridine and non-dihydropyridine calcium blockers are mainly used, depending on the purpose.

Dihydropyridine:

• angina;
• left ventricular hypertrophy;
• atherosclerosis of peripheral vessels;
• pregnancy.

Non-dihydropyridine:

• atherosclerosis of the carotid arteries;
• supraventricular tachycardia.

Mechanism of action

So what are calcium antagonists? These are medications that are distinguished by their ability to effectively lower blood pressure, both and.

Basically, their active action can be traced in the elderly.

Calcium channel inhibitors are considered selective blockers that are located in the sinoatrial and atrioventricular pathways, Purkinje fibers, myofibrils of the myocardium, smooth muscle cells of arteries, veins, capillaries, and skeletal muscles.

Calcium blockers can improve the patency of arteries, veins and small capillaries, and also have the following effects:

• antianginal;
• anti-ischemic;
• lowering high blood pressure;
• organoprotective (cardioprotective, nephroprotective);
• anti-atherogenic;
• normalization of the heart rhythm;
• decrease in pressure in the pulmonary artery and dilatation of the bronchi;
• decreased platelet aggregation.

Indications

Antagonist drugs are prescribed for moderate arterial hypertension, as well as other types of increased pressure in the vessels.

List of drugs

For the treatment of high blood pressure:

1. Amlodipine. It refers to BMCC drugs that are used to eliminate this disease in a single dose of 5 mg per day. If necessary, you can increase the amount of active substance up to 10 mg. It must be taken once a day;
2. Felodipine. The maximum dose is 9 mg per day. It can only be taken once every 24 hours;
3. . Allowed to receive from 40 to 78 mg twice a day;
4. Lercanidipine. The optimal amount of this drug to eliminate the symptoms of hypertension should be from 8 to 20 mg per day. You only need to take it once a day;
5. Verapamil-retard. The maximum single dose of this calcium channel inhibitor drug is 480 mg per day.

;

heart failure with reduced systolic function of the left ventricle;

pregnancy and lactation;

sick sinus syndrome.

It is very difficult to remove excess calcium from the body naturally. If you do not resort to the appropriate drugs, then muscle tissue will begin to suffer from its increased concentration.

According to studies, it was found that a potassium antagonist, like calcium, suppresses the excessive production of a human pancreatic hormone, thereby blocking the entry of ions of the mineral in question into beta cells.

Insulin plays an important role in increasing blood pressure, exerting a strong influence on the release of "exciting" hormones, thickening of the walls of blood vessels and salt retention in the body.

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Review of drugs for hypertension from the group of calcium antagonists:

Elderly people and pregnant women should use the lowest possible dosage of these drugs. Only in this way the body will not be seriously harmed. It is advisable to consult your own cardiologist to prescribe and determine the required dosage. Before taking calcium blockers, you need to read the instructions and contraindications in it to make sure the medicine is safe.

Calcium channel blockers widely used in practical medicine represent a heterogeneous class of drugs. It consists of 4 groups of chemicals, divided into three generations, according to the time of discovery of a particular representative. They have been used for more than 30 years, and the first drug of the group was verapamil, synthesized by A. Flekenstein. There are also calcium antagonists (CA), whose chemical structure does not allow them to be classified into certain categories.

The full list of calcium channel blockers consists of more than 20 drugs, each of which has its own characteristics of influence on human biological tissues. Due to differences in the chemical structure, their effect is not the same and is expressed differently in representatives of different generations of drugs of the class. A number of BPCs have found use in the therapeutic industry, while some are used in neurology and gynecology.

Despite the difference in effects, all known calcium channel blockers have a common mechanism of pharmacological action - they prevent the flow of calcium ions into the cell through voltage-gated slow channels. The latter are called L-channels and are embedded in the membranes of vascular smooth muscle cells, contractile cardiomyocytes, and skeletal muscle sarcolemmas. They are also found in the membranes of neurons of the cerebral cortex (in the dendrites and dendritic spines of neurons).

In addition to L-channels, there are 4 more types of specific proteins in the body, a change in the structure of which changes the intracellular and membrane-bound calcium concentration. The greatest value, in addition to the previously discussed channels of the L type, are voltage-dependent channels of the T-type. They are located in cells with pacemaker activity. They are atypical cardiomyocytes that automatically generate an impulse for myocardial contraction in a given rhythm.

Known calcium channel blockers are characterized by competitive inhibition of L-type receptors, during which the intracellular calcium concentration changes. This disrupts the processes of muscle contraction, makes the contraction weak and incomplete due to the impossibility of complete contact between the actin and myosin chains of muscle proteins. In atypical cardiomyocytes, the effects of calcium channel blockers can inhibit the automatism of atypical cardiomyocytes, providing a useful antiarrhythmic effect.

Classification by chemical structure

In the chemical classification, calcium channel blockers, the list of drugs of which is slightly expanding with new studies, consists of 4 main classes: representatives of the group of diphenylalkylamines, diphenylpiperazines, benzodiazepines and dihydropyridines. All derivatives of these chemicals are (or were) medicinal substances.

Substances of the group of diphenylalkylamines are the very first of those compounds of the class that began to be used as new-galenic preparations. Benzothiazepines are considered the next branch to which calcium channel blockers have branched off. Now the drugs of the group are widely used in therapeutic and obstetric practice.

The group of dihydropyridines is the most dynamically developing and most promising. It consists of the maximum number of medicinal substances, a number of which are included in the standard protocols for the treatment of diseases. Slightly less important are diphenylpiperazines - blockers of slow calcium channels, drugs based on which are often used in neurology.

Generations of calcium antagonist drugs

CCBs (or slow calcium channel blockers) are drugs with a heterogeneous structure. They were developed on the basis of the 4 above-mentioned classes of substances. Medicinal substances that had fewer side effects and were of great therapeutic importance were isolated in advance and became the progenitors of the group of drugs (first generation). Other agents that outperform first-generation CCBs in terms of clinically important effects were classified as II and III generation CCBs in the classification.

Below is a classification of phenylalkylamines, diphenylpiperazines and benzodiazepines by generation, where the original medicinal substances are assigned to a specific class. They are listed as international non-proprietary names.

Diphenylpiperazines and benzodiazepines differ in structure, but these slow calcium channel blockers have a common drawback - they are quickly excreted from the blood and have a small breadth of therapeutic action. In about 3 hours, half of the entire dose of the drug is excreted, therefore, to create a stable therapeutic concentration, it was necessary to prescribe 3- and 4-fold doses during the day.

Due to small differences in therapeutic and toxic doses, an increase in the frequency of taking first-generation drugs causes a risk of intoxication of the body. At the same time, dihydropyridine calcium channel blockers of the first generation are poorly tolerated when administered at such doses. For this reason, their intake is limited with a weakening of therapeutic effects, which is why they are unsuitable for monotherapy.

They were replaced by synthesized and tested calcium channel blockers of the 3rd generation, which are presented only in the group of dihydroperidines. These are drugs that can stay in the blood longer and exert their therapeutic effect. They are more effective and safer, and can be used more widely in a number of pathologies. The classification of these drugs is presented below.

Modern dihydropyridine calcium channel blockers are drugs with an increased duration of action. Their pharmacodynamic characteristics make it possible to prescribe them for 2-fold and single doses during the day. Also, drugs of a number of dihydropyridines are characterized by tissue specificity in relation to the heart and peripheral blood vessels.

Among the representatives of the III generation there are blockers of slow calcium channels, drugs based on which are already widely used in therapy today. Lercanidipine and lacidipine are able to dilate blood vessels, allowing a significant increase in antihypertensive treatment. More often they are combined with diuretics and traditional ACE inhibitors.

Phenylalkylamine series BKK

This section contains calcium channel blockers, the preparations of which have been used for about 30 years. The first is verapamil, which is presented on the pharmacy market in the form of the following drugs: Isoptin, Finoptin, Verogolid. The composition of the drug "Tarka" also contains verapamil in combination with trandolapril.

Substances such as anipamil, falipamil, gallopamil and thiapamil are not on the list of available drugs and are not registered in the pharmacopoeia. For some, trials have not yet been completed to allow them for clinical use. Therefore, verapamil, which is used as an antiarrhythmic, is the safest and most affordable among the CCA phenylalkylamines.

Series of dihydropyridines

Among the dihydropyridines there are calcium channel blockers, the list of drugs based on which is the widest. These medicinal substances are used very often due to the presence of antispasmodic activity. The third generation dihydropyridines are now considered the safest. Among them are lercanidipine and lacidipine.

Lercanidipine is produced by only two pharmacological companies and is available in the form of the drug "Lerkamen" and "Zanidip-Recordati". Lacidipine is available in a wider variety: "Lacipin", "Lacipil" and "Sakur". These brand names are more common, although as the evidence base expands, lacidipine will become more firmly established in therapeutic practice.

Among the representatives of the second generation of dihydropyridines are calcium channel blockers, the preparations of which have the maximum possible number of generics. For example, only amlodipine is produced by more than 20 pharmacological companies under the following names: Amlodipine-Pharma, Tenox, Norvask, Amlocordin, Asomex, Vascopin, Kalchek, Cardiolopin, " Stamlo", "Normodipin", "Amlotop".

Isradipine does not have a list of generics, since this drug is represented by only one trade name - "Lomir" and its modification "Lomir SRO". Also weak distribution characterizes felodipine, riodipine, nitrendipine and nisoldipine. Basically, this trend is due to the presence of "Amlodipine" - a cheap and effective drug. However, in the presence of allergic reactions to Amlodipine, patients are forced to look for a replacement among other members of the dihydropyridine class.

The medicinal substance rhyodipine is represented on the market by the drug "Foridon", and nitrendipine - by "Octidipine". Felodipine in the pharmacy network has two generics - these are "Felodipine" and "Plendil". Nisoldipine is not yet produced by any of the pharmacological companies, and therefore is not available to patients. Nimodipine is offered in the form of Nimotop and Nitop.

Despite the decrease in the importance of the first generations, calcium channel blockers, the drugs of which were used earlier, are widely represented on the market. Nifedipine is the most massive of all short-acting CCBs, as it has the maximum number of generics: Adalat, Vero-nifedipine, Calcigard, Zanifed, Cordaflex, Corinfar, Kordipin, Nicardia , "Nifadil", "Nifedeks", "Nifedikor", "Nifekard", "Osmo", "Nifelat", "Fenigidin". These drugs are affordable, but their prevalence is slowly declining as more effective drugs become available.

Classification of non-specific CCBs

This group of drugs contains calcium channel blockers, the list of drugs of which is limited to 5 substances. These are mibefradil, perhexilin, lidoflazin, caroverine and bepridil. The latter belongs to the class of benzodiazepines, but differs in receptor. It selectively limits the permeability of calcium ions through the T-channels of the pacemakers and is able to block the sodium channels of the cardiac conduction system. In connection with this mechanism of action, bepridil is used as an antiarrhythmic.

An even more promising drug is Mebefradil, which is being tested as an antianginal agent. At the moment, there are a number of publications by authors proving its effectiveness in myocardial infarction and angina pectoris. Therefore, it will be classified as a substance that contains slow calcium channel blockers that can prolong the life of a patient with acute coronary pathology. There are still very few available and highly effective means in this group.

An exception may be the more affordable Lidoflazin. Studies suggest that the latter has the ability not only to expand the arteries of the heart, while lowering blood pressure, but also to stimulate the growth of new blood vessels. The development of collateral circulation in the heart is of great importance. Since calcium channel blockers are predominantly heterogeneous drugs, and lidoflavin is structurally similar to phenylalkylamine, it is natural that it has similar side effects and can only be used outside of acute coronary pathology.

Therapeutic use of "Lidoflazin"

"Lidoflazin" is a representative of the category of drugs with a mild blocking ability in relation to calcium channels. The therapeutic effect of "Lidoflazin" is similar to that of flunarizine, but differs in the expansion of the coronary arteries of the heart, and therefore is used for ischemic myocardial disease without acute manifestations. Preparations in which the active ingredient is lidoflazin have several trade names: Ordiflazin, Klinium, Claviden, Klintab and Korflazin. They can be used for non-severe angina, not associated with the presence of extended stenosis of the coronary arteries of the heart.

The daily dose of "Lidoflazin" is 240-360 mg. In this mode (2-3 times a day), the substance is used for almost six months. The safety of the drug is proved by a number of studies, while caroverine and perhexilin preparations do not have them. These substances are under study for clinical efficacy and toxicity.

Areas of application of the BKK

Modern calcium channel blockers, the list of drugs of which is updated with new substances, are used in therapeutic practice to achieve several types of effects: hypotensive, antianginal, antiischemic and antiarrhythmic. For this purpose, the BKK is used in the following cases:

• with angina pectoris to dilate the vessels of the heart (dihydroperidines, mainly amlodipine);
• with vasospastic angina (amlodipine);
• with Raynaud's syndrome (dihydropiperidines, mainly amlodipine);
• with arterial hypertension (dihydroperidines, mainly amlodipine, less often lercanidipine and lacidipine);
• with supraventricular tachyarrhythmias (phenylalkylamines, mainly verapamil).

In other cases, it is believed that calcium channel blockers, the classification of which is indicated above, are not indicated. The only exception is the group of diphenylpiperazines, represented by "Cinnarizine" and "Flunarizine". These drugs can be used for arterial hypertension in adolescents and pregnant women, as well as in the prevention of vascular disorders in the brain, provoked by hypertensive crises.

Main therapeutic effects of calcium antagonists

In connection with the blockade of voltage-dependent calcium channels, AK has a number of useful therapeutic effects that are important in the treatment of angina pectoris, arterial hypertension, and arrhythmias. This allows the use of selective calcium channel blockers for their treatment, together with a number of auxiliary drugs from other classes.

In angina pectoris, due to calcium antagonists, the arterial vessels of the myocardium expand and a beneficial inhibition of the contractility of the heart muscle occurs. This improves the nutrition of myocardial cells while reducing their oxygen demand. With therapy, anginal attacks develop less frequently and are less prolonged. Also, with vasospastic angina, calcium antagonists are considered the most effective drugs for preventing and stopping an attack of anginal pain.

The drugs of the group contribute to the enhancement of endocardial-epicardial blood flow, improving the blood supply to the myocardium against the background of its hypertrophy. AKs have the property of reducing preload by significantly reducing the amount of blood flowing to the heart. Medicinal substances of the calcium channel blockers group also reduce cardiac afterload, contributing to the stabilization of metabolic processes in ischemic myocardial disease.

In arterial hypertension, calcium channel blockers mediate a decrease in the total peripheral resistance of the vascular bed. The effect is achieved due to the expansion of the muscular walls of the arteries and is accompanied by a decrease in systolic and diastolic pressure in the vessels. Also, calcium blockers weaken the effects of angiotensin on the vascular wall, preventing the growth of blood pressure. They are also second-line drugs necessary for the treatment of hypertension in pregnant women.

Concomitant therapeutic effects

Any calcium channel blockers, the mechanism of action of which is not well understood, have secondary effects. Also, their use is limited by the insufficient information content of the available scientific studies designed to prove the appropriateness of the use of this medicinal substance in chronic myocardial ischemia. The following effects of a group of drugs are also useful here:

• blockade of calcium channels in platelets with a decrease in the rate of their aggregation;
• improvement of renal blood flow with a weakening of RAAS activity and a drop in blood pressure.

Nimodipine is selective for cerebral vessels, and therefore reduces the likelihood of developing secondary vasospasm in subarachnoid hemorrhages. But with CHF, BCC is undesirable, as it worsens the prognosis for life. Only taking amlodipine and felodipine is allowed if there is severe arterial hypertension or angina pectoris that is not corrected by beta-blockers, ACE inhibitors, diuretics. Lercanidipine and lacidipine can be used for the same purpose.

Side effects

Regular intake of short-acting CCBs (nifedipine) is unacceptable, as it causes reflex activation of the sympathetic nervous system and can develop postural hypotension, increasing the risk of ischemic stroke and myocardial infarction. They can also cause a recurrent hypertensive crisis or angina pectoris due to withdrawal syndrome.

Short-acting CCBs are suitable only for relief of crises and angina, but then long-acting ACE inhibitors and beta-blockers should be added. The combined use of CCB with nitrates and ACE inhibitors leads to swelling of the extremities, redness of the skin and face. Without nitrates, the side effect is weaker.

Dihydropyridines cause gingival hyperplasia with prolonged use. The same drugs are contraindicated in stenosis of the aorta and carotid vessels due to the risk of ischemic stroke. Their use is unacceptable in the acute phase of MI and in unstable angina (steal syndrome), and their effectiveness in the secondary prevention of MI has not been proven.

In this article, you will learn about calcium channel blockers and the list of these drugs, for which diseases they are prescribed. Different groups of these drugs, differences between them, their mechanism of action. A detailed description of the most commonly prescribed calcium channel blockers.

Article publication date: 07/01/2017

Article last updated: 06/02/2019

Calcium channel blockers (abbreviated as CCBs), or calcium antagonists (abbreviated as AKs) are a group of medicines that prevent calcium from entering cells through calcium channels. BKK act on:

1. Cardiomyocytes (cells of the heart muscle) - reduce the contractility of the heart.
2. The conduction system of the heart - slow down the heart rate (HR).
3. Vascular smooth muscle dilates the coronary and peripheral arteries.
4. Myometrium - reduce the contractile activity of the uterus.

Calcium channels are proteins in the cell membrane that contain pores that allow calcium to pass through. Due to the entry of calcium into the cells, muscle contraction, the release of neurotransmitters and hormones occur. There are many types of calcium channels, but most CCBs (except cilnidipine) only act on their slow L-type. It is this type of calcium channels that plays the main role in the entry of calcium ions into smooth muscle cells and cardiomyocytes.

Click on photo to enlarge

There are also other types of calcium channels:

• P-type - located in the cells of the cerebellum.
• N-type - localized in the brain.
• R - located in the cells of the cerebellum and other neurons.
• T - are located in neurons, cells with pacemaker activity, osteocytes (bone tissue cells).

CCB is most often prescribed for the treatment of arterial hypertension (AH) and angina pectoris (CHD), especially when these diseases are combined with diabetes mellitus. AKs are used to treat certain arrhythmias, subarachnoid hemorrhage, Raynaud's syndrome, cluster headache prevention, and prevention of preterm delivery.

Most often, CCBs are prescribed by cardiologists and therapists. Independent use of BPC is prohibited due to the risk of developing serious complications.

BKK groups

In clinical practice, the following groups of BCC are distinguished:

• Dihydropyridines (nifedipine group) - act mainly on blood vessels, therefore they are used to treat hypertension.
• Phenylalkylamines (verapamil group) - act on the myocardium and the conduction system of the heart, therefore they are prescribed mainly for the treatment of angina pectoris and arrhythmias.
• Benzodiazepines (the diltiazem group) are an intermediate group that has the properties of dihydropyridines and phenylalkylamines.

There are 4 generations of BKK:

1. 1st generation - nifedipine, verapamil, diltiazem.
2. 2nd generation - felodipine, isradipine, nimodipine.
3. 3rd generation - amlodipine, lercanidipine.
4. 4th generation - cilnidipine.

Mechanism of action

CCBs bind to slow calcium channel receptors through which most of the calcium ions enter the cell. Calcium is involved in the functioning of the sinus and atrioventricular nodes (regulate the heart rhythm), in contractions of cardiomyocytes and vascular smooth muscles.

By influencing these channels, BPC:

• They weaken the contractions of the heart, reducing its need for oxygen.
• They reduce vascular tone and eliminate their spasm, reducing blood pressure (BP).
• Reduce the spasm of the coronary arteries, thereby increasing the blood supply to the myocardium.
• Slow down heart rate.
• Impair platelet aggregation.
• They counteract the formation of new atherosclerotic plaques, inhibit the division of smooth muscle cells of the vascular wall.

Each of the individual drugs does not have all these properties at once. Some of them affect the vessels more, others - on the heart.

Indications for use

Doctors prescribe calcium channel blockers to treat the following conditions:

• AG (high blood pressure). By causing vasodilation, CCBs reduce systemic vascular resistance, which lowers blood pressure. These drugs affect mainly the arteries and have minimal effect on the veins. CCBs are included in the five main groups of antihypertensive drugs.
• Angina pectoris (pain in the region of the heart). CCBs dilate blood vessels and decrease the contractility of the heart. Systemic vasodilation caused by the use of dihydropyridines reduces blood pressure, thereby reducing the load on the heart, which leads to a decrease in its oxygen demand. CCBs that act primarily on the heart (verapamil, diltiazem) reduce heart rate and weaken heart contractions, which leads to a decrease in its oxygen demand, making them effective remedies for angina pectoris. CCBs can also dilate the coronary arteries and prevent their spasm by improving myocardial blood supply. Due to these effects, CCBs - together with beta-blockers - are the mainstay of pharmacotherapy for stable angina.
• supraventricular arrhythmias. Some CCBs (verapamil, diltiazem) affect the sinus and atrioventricular node, so they can effectively restore a normal heart rhythm in patients with atrial fibrillation or flutter.
• Raynaud's disease (spastic vasoconstriction, most often affecting the hands and feet). The use of nifedipine helps to eliminate arterial spasm, thereby reducing the frequency and severity of attacks of Raynaud's disease. Sometimes amlodipine or diltiazem is used for this purpose.
• Cluster headache (recurring attacks of very severe pain on one side of the head, usually around the eye). Verapamil helps reduce the severity of seizures.
• Relaxation of the muscles of the uterus (tocolysis). Doctors sometimes use nifedipine to prevent preterm labor.
• Hypertrophic cardiomyopathy (a disease in which there is a strong thickening of the walls of the heart). Calcium channel blockers (verapamil) weaken the contractions of the heart, so they are prescribed for the treatment of hypertrophic cardiomyopathy if patients have contraindications to taking beta-blockers.
• (increased pressure in the pulmonary artery). Pulmonary hypertension is treated with nifedipine, diltiazem, or amlodipine.
• Subarachnoid hemorrhage (bleeding into the space surrounding the brain). To prevent vasospasm, nimodipine is used, which has a selective effect on cerebral arteries.

Contraindications

Calcium channel blockers drugs have their own contraindications, which are clearly spelled out in the instructions for the drug. For instance:

1. Means from the groups of verapamil and diltiazem are contraindicated in patients with bradycardia, pathology of the conduction system of the heart or systolic heart failure. Also, they should not be given to patients already taking beta-blockers.
2. All calcium antagonists are contraindicated in patients with low blood pressure, unstable angina, severe aortic stenosis.
3. CCB is not used in pregnant and breastfeeding women.

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Side effects

Side effects of BPC depend on the properties of the group of these drugs:

• Action on the myocardium can cause hypotension and heart failure.
• Action on the conduction system of the heart can lead to blockades or arrhythmias.
• The effect on the vessels sometimes causes hot flashes, swelling, headaches, rashes.
• Other side effects include constipation, gynecomastia, increased sensitivity to sunlight.

Dihydropyridine CCBs

Dihydropyridines are the most commonly prescribed calcium antagonists. These drugs are mainly used to lower blood pressure. The most famous drugs from this group include:

• Nifedipine is one of the first CCBs that acts primarily on blood vessels. Assign to reduce blood pressure in hypertensive crises, eliminate the symptoms of vasospastic angina, treat Raynaud's disease. Nifedipine rarely exacerbates heart failure, since the deterioration in myocardial contractility is compensated by a decrease in the load on the heart. There are long-acting drugs that are used to treat hypertension and angina pectoris.
• Nicardipine - this drug, like nifedipine, affects blood vessels. Used to prevent angina attacks and treat hypertension.
• Amlodipine and felodipine are among the most commonly prescribed CCBs. They act on blood vessels, do not worsen the contractility of the heart. They have a long-term effect, making them convenient for the treatment of hypertension and angina pectoris. Their use is especially useful in vasospastic angina. Side effects associated with the expansion of the arteries (headache, hot flashes), they can pass in a few days.
• Lercanidipine and isradipine - similar in characteristics to nifedipine, are used only for the treatment of arterial hypertension.
• Nimodipine - this drug has a selective action of the cerebral artery. Due to this property, nimodipine is used to prevent secondary spasm of cerebral arteries in subarachnoid hemorrhage. For the treatment of others, nimodipine is not used, since there is no evidence of its effectiveness for these purposes.

Side effects of all dihydropyridine CCBs are associated with vasodilation (headache, hot flashes), they may disappear within a few days. Edema in the legs also often develops, which is difficult to eliminate with diuretics.

Phenylalkylamines

Calcium channel blockers from this group mainly affect the myocardium and the conduction system of the heart, therefore, they are most often prescribed for the treatment of angina pectoris and arrhythmias.

Verapamil is practically the only CCA from the group of phenylalkylamines used in clinical medicine. This drug worsens the contractility of the heart, and also affects the conduction in the atrioventricular node. Because of these effects, verapamil is used to treat angina pectoris and supraventricular tachycardia. Side effects include worsening heart failure, bradycardia, a drop in blood pressure, worsening conduction disturbances in the heart. Verapamil is contraindicated in patients already taking beta-blockers.

Benzodiazepines

Benzodiazepines are intermediate between dihydropyridines and phenylalkylamines, so they can both dilate blood vessels and impair cardiac contractility.

An example of a benzodiazepa is diltiazem. This drug is most often used for angina pectoris. There is a form of release of prolonged action, which is prescribed for the treatment of hypertension. Since diltiazem affects the conduction system of the heart, it should be combined with caution with beta-blockers.

Other Precautions While Using CCB

Any drug from the CCB group can be used only as directed by a doctor. The following points should be taken into account:

1. If you are taking a CCB drug, you should not drink grapefruit juice. This prohibition is due to the fact that it increases the amount of the drug entering the blood. As a result of this, your blood pressure may suddenly drop, which is sometimes quite dangerous. Grapefruit juice affects almost all calcium channel blockers except amlodipine and diltiazem. Juice from oranges and other fruits can be drunk.
2. Check with your doctor before taking any medication, including herbal medicines, in combination with calcium antagonists.
3. Be prepared for long-term use of CCBs in the treatment of hypertension. Some patients stop taking antihypertensive drugs on their own as soon as their blood pressure levels return to normal, but doing so can put their health at risk.
4. If you have angina and suddenly stop taking these blockers, you may experience heart pain.

Calcium channel blockers (drugs) are a group of drugs aimed at preventing the passage of calcium through calcium channels and its penetration into the middle of cells. Another name is calcium antagonists (AK); slow calcium channel blockers (CBCC).

Calcium channels are protein structures that carry calcium ions between cells. Thanks to these particles, an electrical impulse is formed and conducted. They also create conditions for the process of contraction of the muscle fibers of the heart and the walls of blood vessels.

These drugs are often used to treat coronary heart disease, hypertension, and arrhythmias.

Mechanism of action of BPC

The main effect of calcium antagonists is to contain calcium ions in the calcium passageways on their way to the cells of the body. At the same time, the vessels that supply the heart muscle with blood become wider, and the quality of the blood supply to the heart increases. These processes lead to a better supply of oxygen to the myocardium and the removal of metabolic products.

CCBs have three main effects on the body:

1. Antiarrhythmic effect on: precardiac gastric node (inhibits conduction, reduces automatism, increases the efficiency of the refractory period); sinoatrial node (reduces automatism, lowers heart rate, lowers the heart's need for oxygen).
2. Antianginal effect on: myocardium (reduces the strength of heart contractions, lowers the work of the heart, reducing the need for oxygen to the heart); coronary vessels (reduces their resistance, increases the speed of blood flow, accelerates the supply of blood to the heart).
3. Hypotensive effect on: peripheral vessels (reduces total resistance, lowers blood pressure).

Based on the chemical structure and the time when the BPC were discovered, they are classified into the following groups:

• Dihydropyridine- act on blood vessels, are used to treat arterial hypertension. This is the main group of AK, it is in constant development and consists of many varieties of medications.
• Phenylalkylamine- affect the myocardium and the conduction system of the heart muscle, are prescribed in the treatment of various types of arrhythmia and angina pectoris.
• benzodiazepine- This is a transitional group of BMCs, medicines that have the properties of both dihydropyridine BMCs and phenylalkylamine BCCs.

There are four generations of calcium antagonists:

The scope of the use of calcium channel blockers is quite extensive, discussed in more detail below:

Medications, like Verapamil, Diltiazem, mostly affect the heart muscle, lower the heart rate (HR), due to this effect, the heart's need for oxygen becomes less, which shows the effectiveness of these drugs.

Another advantage of calcium antagonists in angina pectoris is that the blood supply to the myocardium improves, because. they dilate the coronary arteries and prevent spasms. Complex treatment of CCB and β-blockers is the basis for the treatment of angina pectoris.

• Violation of the heart rhythm (arrhythmia). Some CCB drugs affect the sinus and atrioventricular nodes, which positively affects the heart rate of patients with atrial fibrillation.
• Raynaud's disease (angiotrophoneurosis with a primary lesion of small terminal arteries and arterioles). The use of Nifedipine helps to eliminate arterial spasms, as a result of which various manifestations of this disease are reduced. For this purpose, medications such as Amplodipine and Diltiazem can also be used.
• Bundle headache (acute recurring attacks of pain, concentrated in the eye area). The drug Verapamil helps to reduce the severity of pain attacks.
• Hypertrophic Cardiomyopathy (HCM - thickening of the wall of the left and in rare cases of the right ventricle of the heart muscle). CCB, namely Verapamil, is used to reduce the contractility of the heart. If the patient has contraindications to the use of β-blockers, then calcium channel blockers are prescribed for the treatment of this disease.
• Huntington's syndrome.
• Alcohol addiction.
• encephalopathy.

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Composition of calcium channel blockers

The active substance that is in the composition of calcium channel blockers varies, depending on the belonging of an individual drug to a particular chemical group. In addition, the composition of medications also includes additional substances, due to which the drug is formed for its further use.

In addition to drugs containing only BPC substances, combined medications are produced, which, in addition to BPC, include medicinal substances that belong to other chemical and drug groups. such a combination of substances is due to the complex effect of the combination of certain active substances for the treatment of such diseases that require an integrated approach (cardiomyopathy, angina pectoris).

The release form of calcium antagonists depends on the way they are used. For oral use, they are made in the form of tablets or capsules. For intravenous injection - solution.

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Application features

The main feature of slow calcium channel blockers is that these medications have several one-time effects: they normalize blood flow and expand the walls of blood vessels.

It is also worth highlighting such positive aspects of the use of BKK:

1. Increase urine production. Diuretic action helps to lower blood pressure faster. this is due to the inhibition of the process of reverse absorption of sodium into the tubules of the kidneys.
2. Suppression of the contractile function of the heart. When the contraction of the heart weakens, the systolic (upper) pressure decreases.
3. antiplatelet effect. It manifests itself in the fact that BCC does not allow platelets to stick together and form blood clots.

Application methods

Only a doctor can determine the appropriate drug and its dosage, taking into account the characteristics of the patient's health status, previous diseases, etc.

Rarely used in the treatment of hypertension. Often prescribed for treatment supraventricular arrhythmias.

The dosage increases gradually until a stable therapeutic effect is obtained.

For the treatment of other diseases, calcium antagonist preparations are prescribed solely taking into account the individual characteristics of each patient.

Side effects

Do not forget that the use of any drug may have a side effect on the human body due to individual characteristics.

The use of calcium channel blockers can have the following side effects:

• Pain in the head, dizziness.
• Redness of the face, skin, dermatitis, vasculitis.
• Tachycardia.
• Swelling of the extremities.
• Decreased inotropic function of the myocardium.
• AV conduction slows down.
• Decreased heart rate.
• Attacks of nausea, vomiting, diarrhea, constipation.

Contraindications

It is also worth remembering before you start taking calcium channel blockers that there are certain contraindications for their use, namely:

• Myocardial infarction. Simultaneous reception of CCB can lead to death.
• Tachycardia. Taking drugs of the Nifedipine group (dihydropyridine CCBs) can lead to an increase in heart rate.
• Bradycardia. (drugs of the Verapamil group).
• Heart failure in acute and chronic form. Categorical incompatibility with the reception of BCC. It can lead to stages of decompensation, pulmonary edema, etc.
• During pregnancy and lactation.
• Children under the age of 14. An exception is Verapamil, which is prescribed in rare cases and with extreme caution.
• Individual intolerance to individual components of medications.
• Renal and liver failure.

Contraindications to the use of BPC

Medications of this group are more often used among others. They are used to treat hypertension. The most popular drugs in this group:

• Nifedipine is one of the first calcium antagonist drugs. It is used for hypertension and hypertensive crisis.
• Nicardipine - like Nifedipine, it affects blood vessels. Used to treat angina pectoris and hypertension.
• Amplodipine, Felodipine are commonly used drugs. They affect the vessels and do not worsen the contractile function of the heart. They are effective in vasospastic angina pectoris. They have minor side effects.
• Lercanidipine, Isradipine - similar to Nifedipine, prescribed for the treatment of hypertension.
• Nimodipine - has a selective effect on the arteries of the brain. Effective in the treatment of secondary spasm of the cerebral arteries.

BPC of the phenylalkylamine group

Medications of this group affect the myocardium and the impulse conduction system. They are mainly used in the treatment of angina pectoris and arrhythmias. A prominent representative, which is most often used, is. Reduces the contractile function of the heart and affects AV conduction. Incompatible with blockers.

This is an intermediate group of drugs that has the properties to dilate blood vessels and lower the contractility of the heart. One of the representatives Diltiazem. Cautious use in combination with β-blockers.

Interaction with other drugs

As mentioned earlier, phenylalkylamines should not be combined with β-blockers. Also, some CCBs are incompatible with Novocainamide and anticonvulsants.

It is possible to increase the side effects of CCB in combination with non-steroidal anti-inflammatory drugs and sulfonamides.

Joint reception with ACE inhibitors, nitrates, diuretics is possible.

In rare cases, CCB does not have the desired effect, so the drug is canceled and another, more suitable one is prescribed.

CCB withdrawal syndrome

CCB drugs should be discontinued gradually, because. abrupt cancellation can provoke vasospasm (increased blood pressure, angina pectoris). Drugs of the Verapamil group have a less pronounced withdrawal syndrome, or it may be completely absent.