What medicines are there for blocks. A complete overview of all types of blockers: selective, non-selective, alpha, beta. With heart failure

Oddly enough, humanity has only started talking about beta blockers in the last few years, and this is not at all related to the moment these drugs were invented. Beta blockers have been known to medicine for a long time, but now every conscious patient suffering from pathology of the heart and blood vessels considers it necessary to have at least minimal knowledge about what drugs can be used to defeat the disease.

The history of the appearance of drugs

The pharmaceutical industry has never stood still - it was pushed to success by all the updated facts about the mechanisms of a particular disease. In the 30s of the last century, doctors noticed that the heart muscle begins to work much better if it is influenced by certain means. A little later, the substances were called beta-agonists. Scientists have found that these stimulants in the body find a "pair" for interaction, and in research twenty years later, the theory of the existence of beta-adrenergic receptors was first proposed.

A little later, it was found that the heart muscle is most susceptible to adrenaline, which causes cardiomyocytes to contract at a breakneck pace. This is how heart attacks happen. To protect the beta receptors, scientists intended to create special tools that prevent the harmful effects of the aggressive hormone on the heart. Success was achieved in the early 60s, when protenalol was invented - a pioneer beta blocker, protector of beta receptors. Due to the high carcinogenicity, protenalol was modified and propranolol was released for mass production. The developers of the theory of beta receptors and blockers, as well as the drug itself, received the highest mark in science - the Nobel Prize.

Operating principle

Since the release of the first drug, pharmaceutical laboratories have developed more than a hundred of their varieties, but in practice no more than a third of the funds are used. The latest generation drug - Nebivolol - was synthesized and certified for treatment in 2001.

Beta blockers are medicines for stopping heart attacks by blocking adrenoreceptors that are sensitive to the release of adrenaline.

Their mechanism of action is as follows. The human body under the influence of certain factors produces hormones and catecholamines. They are able to irritate beta 1 and beta 2 receptors located in different places. As a result of such exposure, the body undergoes significant negative effects, and especially the heart muscle suffers.

For example, it is worth remembering what feelings a person feels when, in a state of stress, the adrenal glands make an excessive release of adrenaline and the heart begins to beat ten times faster. In order to somehow protect the heart muscle from such irritants, blockers have been created. These drugs block the adrenoreceptors themselves, susceptible to the effects of adrenaline on them. By breaking this ligament, it was possible to significantly facilitate the work of the heart muscle, make it contract more calmly and throw blood into the bloodstream with less pressure.

Consequences of taking drugs

Thus, the work of beta blockers can reduce the frequency of angina attacks (increased heart rate), which are the direct cause of sudden death in humans. Under the influence of beta blockers, the following changes occur:

• blood pressure normalizes
• decreased cardiac output,
• the level of renin in the blood decreases,
• CNS activity is inhibited.

As established by doctors, the largest number of beta-adrenergic receptors is localized in the cardiovascular system. And this is not surprising, because the work of the heart ensures the vital activity of every cell of the body, and the heart becomes the main target of adrenaline, a stimulating hormone. When recommending beta blockers, doctors also note their detrimental effect, so they have such contraindications: COPD, diabetes mellitus (for some), dyslipidemia, and the patient's depressive state.

What is drug selectivity

The key role of beta blockers is to protect the heart from atherosclerotic lesions, the cardioprotective effect that this group of agents has is to provide antiarrhythmic action by reducing ventricular regression. Despite all the bright prospects for the use of drugs, they have one significant drawback - they affect both the necessary beta-1-adrenergic receptors and beta-2-adrenergic receptors, which do not need to be inhibited at all. This is the main disadvantage - the impossibility of selecting some receptors from others.

The selectivity of drugs is considered to be the ability to selectively act on beta-adrenergic receptors, blocking only beta-1-adrenergic receptors, and not affecting beta-2-adrenergic receptors. Selective action can significantly reduce the risk of side effects of beta blockers, sometimes observed in patients. That is why doctors are currently trying to prescribe selective beta blockers, i.e. "smart" drugs that can distinguish beta-1 from beta-2 adrenoreceptors.

Classification of drugs

In the process of creating drugs, many drugs were produced, which can be classified as follows:

• selective or non-selective beta blockers (based on selective action for beta-1 and beta-2 blockers),
• lipophilic agents or hydrophilic (based on solubility in fats or water),
• drugs with and without intrinsic sympathomimetic activity.

Today, three generations of medicines have already been released, so there is an opportunity to be treated with the most modern means, contraindications and side effects of which are minimized. Medicines are becoming more affordable for patients with various complications of cardiopathology.

Classification refers to non-selective agents for first-generation drugs. The “test of the pen” at the time of the invention of even such drugs was successful, since patients were able to stop heart attacks even with beta blockers that are imperfect today. Nevertheless, at that time this was a breakthrough in medicine. So, Propranolol, Timolol, Sotalol, Oxprenolol and other drugs can be classified as non-selective drugs.

The second generation is already more “smart” drugs that distinguish beta-1 from beta-2. Cardioselective beta-blockers are Atenolol, Concor (read more in this article), Metoprolol succinate, Lokren.

The third generation is recognized as the most successful due to its unique properties. They are able not only to protect the heart from an increased release of adrenaline, but also have a relaxing effect on blood vessels. List of drugs - Labetalol, Nebivolol, Carvedilol and others. The mechanism of their effect on the heart is different, but the means are able to achieve a common result - to normalize cardiac activity.

Features of drugs with ICA

As it turned out in the process of testing drugs and using them in patients, not all beta blockers are able to completely inhibit the activity of beta-adrenergic receptors. There are a number of drugs that initially block their activity, but at the same time stimulate it. This phenomenon is called internal sympathomimetic activity - ICA. It is impossible to evaluate these funds negatively and call them useless. As the results of studies show, when taking such drugs, the work of the heart also slowed down, however, with their help, the pumping function of the organ did not significantly decrease, peripheral vascular resistance increased, and atherosclerosis was provoked least of all.

If such drugs are taken for a long time, then beta-adrenergic receptors are stimulated chronically, which leads to a decrease in their density in tissues. Therefore, if beta-blockers were suddenly stopped being taken, this did not provoke a withdrawal syndrome - the patients did not suffer from hypertensive crises, tachycardia and angina pectoris. In critical cases, the cancellation could provoke a fatal outcome. Therefore, doctors note that the therapeutic effect of drugs with internal sympathomimetic activity is no worse than classic beta blockers, but the absence of negative effects on the body is significantly lower. This fact distinguishes the group of funds among all beta blockers.

Feature of lipophilic and hydrophilic drugs

The main difference between these funds is where they dissolve better. Lipophilic representatives are able to dissolve in fats, and hydrophilic - only in water. In view of this, in order to remove lipophilic substances, the body needs to pass them through the liver in order to decompose them into components. Water-soluble beta blockers are more readily accepted by the body because they are not passed through the liver, but are evacuated from the body unchanged in the urine. The action of these drugs is much longer than that of lipophilic representatives.

But fat-soluble beta blockers have an undeniable advantage over hydrophilic drugs - they can penetrate the blood-brain barrier that separates the blood system from the central nervous system. So, as a result of taking such drugs, it was possible to significantly reduce the mortality rate among those patients who suffered from coronary heart disease. However, while having a positive effect on the heart, fat-soluble beta blockers contribute to sleep disturbance, provoke severe headaches, and can cause depression in patients. Bisoprolol is a universal representative - it is able to dissolve perfectly both in fats and in water. Therefore, the body itself decides how to remove the residues - in case of liver pathology, for example, the drug is perfectly excreted by the kidneys, which take on this responsibility.

In this article, we will consider drugs beta-blockers.

A very important role in the regulation of the functions of the human body is played by catecholamines, which are adrenaline with norepinephrine. They are released into the blood and act on especially sensitive nerve endings called adrenoreceptors. They are divided into two large groups. The first is alpha-adrenergic receptors, and the second is found in many human organs and tissues.

Detailed description of this group of drugs

Beta-blockers, or BAB for short, are a group of drugs that bind beta-adrenergic receptors and prevent catecholamines from acting on them. Such preparations are particularly useful in cardiology.

In the case of activation of β1-adrenergic receptors, an increase in the frequency and strength of heart contractions occurs, and in addition, the coronary arteries expand, the level of conduction and automatism of the heart increases. Among other things, the breakdown of glycogen in the liver is enhanced and energy is produced.

In the case of excitation of β2-adrenergic receptors, the walls of blood vessels and bronchial muscles relax, uterine tone decreases during pregnancy, insulin secretion increases along with the breakdown of fat. Thus, the process of stimulation of beta-adrenergic receptors through catecholamines leads to the mobilization of all forces, which contributes to active life.

A list of new generation beta-blockers will be presented below.

The mechanism of action of drugs

These drugs are able to reduce the frequency along with the force of heart contractions, thereby lowering blood pressure. As a result, oxygen consumption by the heart muscle decreases.

There is an elongation of diastole - a period of rest and general relaxation of the heart, during which the vessels are filled with blood. The improvement of coronary perfusion is also facilitated by a decrease in diastolic intracardiac pressure. There is a process of redistribution of blood flow from normally vascularized areas to ischemic areas, as a result of which a person's tolerance to physical activity increases.

Beta-blockers have antiarrhythmic effects. They are able to suppress the cardiotoxic and arrhythmogenic effects of catecholamines, and in addition, they prevent the accumulation of calcium ions in the heart cells, which impair energy metabolism in the myocardial region.

The list of beta-blockers is very extensive.

Classification of drugs in this group

Substances presented are quite a large group of medicines. They are classified according to many criteria. Cardioselectivity is the ability of a drug to block only β1-adrenergic receptors, without affecting β2-adrenergic receptors located in the vascular and bronchial walls. The greater the selectivity of beta-1-blockers, the less danger in their use in concomitant pathologies of the respiratory canals and peripheral vessels, and in addition, in diabetes mellitus. But selectivity is a relative concept. In the case of prescribing the drug in excessive doses, the degree of selectivity decreases.

Some beta-blockers are characterized by the presence of internal sympathomimetic activity. It lies in the ability to some extent cause stimulation of beta-adrenergic receptors. Compared to conventional beta-blockers, such drugs slow down heart rate and contraction much less, less often lead to withdrawal symptoms. In addition, they do not have such a negative effect on lipid metabolism.

Some selective beta-blockers can additionally dilate blood vessels, that is, they are endowed with vasodilatory properties. This mechanism is usually realized through internal pronounced sympathomimetic activity.

The duration of exposure most often directly depends on the characteristics of the chemical structure of selective and non-selective beta-blockers. Lipophilic agents can act for several hours and are quickly excreted from the body. Hydrophilic drugs, such as Atenolol, are effective for a longer time and may be prescribed less frequently. To date, long-acting lipophilic drugs have also been developed, for example, Metoprolol Retard. In addition, there are beta-blockers with a very short duration of exposure, only up to thirty minutes, as an example, the drug "Esmolol" can be called.

Non-cardioselective drugs

The group of non-cardioselective beta-blockers includes drugs that do not have intrinsic sympathomimetic activity. These are the following:

• Means based on propranolol, for example, Anaprilin and Obzidan.
• Preparations based on nadolol, for example, Korgard.
• Medicines based on sotalol: "Sotahexal" along with "Tenzol".
• Funds based on timolol, for example "Blocarden".

The list of beta-blockers with sympathomimetic activity includes the following drugs:

• Medicines based on oxprenolol, for example Trazikor.
• Pindolol-based products, such as Wisken.
• Preparations based on alprenolol, for example Aptin.
• Medications based on penbutolol, for example, Betapressin along with Levatol.
• Funds based on bopindolol, for example, "Sandorm".

Among other things, Bucindolol has sympathomimetic activity along with Dilevalol, Karteolol and Labetalol.

The list of beta-blockers does not end there.

Cardioselective drugs

Cardioselective drugs include the following drugs that do not have intrinsic sympathomimetic activity:

• Medicines based on metoprolol, for example Betaloc along with Corvitol, Metozok, Metocard, Metokor, Serdol and Egilok.
• Preparations based on atenolol, for example "Betacard" along with "Stenormin".
• Betaxolol-based products, such as Betak, Kerlon and Lokren.
• Esmolol-based medicines, such as Breviblok.
• Preparations based on bisoprolol, for example, "Aritel", "Bidop", "Biol", "Biprol", "Bisogamma", "Bisomor", "Concor", "Corbis", "Cordinorm", "Coronal", "Niperten" and Tirez.
• Medications based on carvedilol, for example, Acridilol, along with Bagodilol, Vedicardol, Dilatrend, Carvedigamma, Karvenal, Coriol, Recardium and Talliton.
• Preparations based on nebivolol, such as Binelol along with Nebivator, Nebikor, Nebilan, Nebilet, Nebilong and Nevotenz.

The following cardioselective drugs have sympathomimetic activity: Acecor along with Sektral, Kordanum and Vasakor.

Let's continue the list of new generation beta-blockers.

Medications with vasodilatory properties

Non-cardioselective drugs in this category include drugs such as Amozulalol along with Bucindolol, Dilevalol, Labetolol, Medroxalol, Nipradilol and Pindolol.

Carvedilol, Nebivolol and Celiprolol are equated to cardioselective drugs.

How does the action of beta-blockers differ?

Long-term exposure agents include Bopindolol along with Nadolol, Penbutolol and Sotalol. And among the beta-blockers with ultra-short action, it is worth mentioning Esmolol.

Use against the background of angina pectoris

In many cases, such drugs serve as one of the leading drugs for the treatment of angina pectoris and the prevention of attacks. Unlike nitrates, these agents do not cause drug resistance over long-term use. Beta-blockers are able to accumulate in the body, which makes it possible to reduce the dosage of the drug after a while. These medicines serve to protect the heart muscle, improving the prognosis by reducing the risk of a second heart attack. The antianginal activity of such drugs is the same. They need to be selected depending on the duration of the effect and side reactions.

Start therapy with a small dosage, which is gradually increased to an effective one. The dose is selected in such a way that the heart rate at rest is not less than fifty per minute, and the level of systolic pressure is not less than one hundred millimeters of mercury. Upon reaching the therapeutic effect, angina attacks stop, exercise tolerance improves. Against the background of progress, the dosage should be reduced to the minimum effective.

Long-term use of high doses of such drugs is considered inappropriate, as this increases the risk of adverse reactions. In case of insufficient effectiveness, it is better to combine these drugs with other groups of drugs. Such funds should not be abruptly canceled, as a withdrawal syndrome may appear. Beta-blockers are especially indicated if angina pectoris is combined with sinus tachycardia, glaucoma, arterial hypertension, or constipation.

The newest beta-blockers are effective in myocardial infarction.

Treatment for a heart attack

Early use of BAB against the background of a heart attack helps to limit necrosis of the heart muscle. This significantly reduces mortality and the risk of recurrent heart attack. In addition, the risk of cardiac arrest is reduced.

A similar effect is found with drugs without sympathomimetic activity, it is preferable to use cardioselective drugs. In particular, they are useful in the combination of a heart attack with such ailments as arterial hypertension, sinus tachycardia, post-infarction angina and tachysystolic form of atrial fibrillation.

These drugs can be prescribed to patients immediately upon admission to the hospital, provided that there are no contraindications. In the absence of side effects, treatment should continue for at least a year after a heart attack.

The use of BAB in chronic heart failure

The use of beta-blockers in heart failure is currently being studied. It is believed that they should be used in the combination of heart failure with angina pectoris. Pathologies in the form of rhythm disturbances, arterial hypertension are also grounds for prescribing this group of drugs to patients.

Use in hypertension

BAB is prescribed for the treatment of hypertension, which is complicated by ventricular hypertrophy. They are also widely used among young patients who lead an active lifestyle. This category of drugs is prescribed in the case of a combination of arterial hypertension with cardiac arrhythmias, and in addition, after a heart attack.

How else can you use the new generation beta-blockers from the list?

Use in cardiac arrhythmias

BAB is widely used for atrial fibrillation and flutter, and in addition, against the background of poorly tolerated sinus tachycardia. They can also be prescribed in the presence of ventricular arrhythmias, however, the effectiveness in this case will be less pronounced. BAB in combination with potassium preparations is used to treat arrhythmias caused by

What are the possible side effects from the work of the heart?

BAB can inhibit the ability of the sinus node to generate impulses that cause heart contractions. These drugs can slow the heart rate to less than fifty per minute. This side effect is less pronounced in BABs with sympathomimetic activity.

Drugs in this category can cause varying degrees of atrioventricular block. They reduce the force of heart contraction. In addition, BABs lower blood pressure. Medicines of this group cause spasms of peripheral vessels. Patients may experience cold extremities. New generation beta-blockers reduce renal blood flow. Due to the deterioration of blood circulation during treatment with these drugs, sometimes patients experience severe weakness.

Adverse reactions from the respiratory system

BABs can cause bronchospasm. This side effect is less pronounced among cardioselective drugs. However, their dosages, which are effective against angina pectoris, are often quite high. The use of high doses of these drugs can provoke sleep apnea along with temporary respiratory arrest. BABs can worsen the course of an allergic reaction to insect stings, as well as to drugs and food allergens.

The reaction of the nervous system

"Propranolol" along with "Metoprolol" and other lipophilic BAB can penetrate into brain cells through the blood-brain barrier. In this regard, they can cause headaches, sleep disturbance, dizziness, memory impairment, and depression. In severe cases, hallucinations, seizures or coma may occur. These side reactions are much less pronounced in hydrophilic drugs, in particular, Atenolol.

Treatment of BAB is sometimes accompanied by impaired nerve conduction. This leads to weakness in the muscles, fatigue and reduced stamina.

Metabolic reaction

Non-selective β-blockers are able to suppress the production of insulin. Also, these drugs significantly inhibit the processes of glucose mobilization from the liver, which contributes to the development of prolonged hypoglycemia in patients with diabetes. Hypoglycemia, as a rule, promotes the release of adrenaline into the blood, which acts on alpha-adrenergic receptors. This results in a significant rise in pressure. Therefore, if it is necessary to prescribe a BAB to a patient with concomitant diabetes, it is better to give preference to cardioselective drugs or change them to calcium antagonists.

Many BABs, especially non-selective ones, reduce the content of normal cholesterol in the blood and, accordingly, increase the level of bad cholesterol. True, such drugs as "Carvedilol" along with "Labetolol", "Pindolol", "Dilevalol" and "Celiprolol" are deprived of this drawback.

What other side effects are possible?

Treatment of BAB in some cases may be accompanied by sexual dysfunction, and in addition, erectile dysfunction and loss of sexual desire. To date, the mechanism of this effect is unclear. Among other things, BAB can cause skin changes, which, as a rule, manifests itself in the form of erythema, rash, and symptoms of psoriasis. In rare cases, hair loss occurs along with stomatitis. The most serious side effect is the inhibition of hematopoiesis with the occurrence of thrombocytopenic purpura and agranulocytosis.

Contraindications to the use of BAB

Beta-blockers have many different contraindications and are considered completely prohibited in the following situations:

A relative contraindication to the prescription of drugs in this category is Raynaud's syndrome, along with atherosclerosis of peripheral arteries, which is accompanied by the occurrence of intermittent claudication.

So, we have reviewed the list of beta-blockers. We hope that the information provided was useful to you.

Content

The action on beta-adrenergic receptors of adrenaline and norepinephrine in diseases of the heart and blood vessels can lead to fatal consequences. In this situation, drugs grouped into groups of beta-blockers (BAB) not only make life easier, but also prolong it. Studying the topic of BAB will teach you to better understand your body when getting rid of the disease.

What are beta blockers

Adrenoblockers (adrenolytics) are a group of drugs with a common pharmacological action - neutralization of adrenaline receptors in blood vessels and the heart. Medications "turn off" the receptors that respond to adrenaline and norepinephrine, and block the following actions:

• a sharp narrowing of the lumen of blood vessels;
• increased blood pressure;
• antiallergic effect;
• bronchodilator activity (expansion of the lumen of the bronchi);
• increase in blood glucose levels (hypoglycemic effect).

The drugs affect β2-adrenergic receptors and β1-adrenergic receptors, causing the opposite action of adrenaline and norepinephrine. They dilate blood vessels, lower blood pressure, narrow the lumen of the bronchi and reduce blood sugar levels. When beta1-adrenergic receptors are activated, the frequency and strength of heart contractions increase, coronary arteries expand.

Due to the action on β1-adrenergic receptors, the conduction of the heart improves, the breakdown of glycogen in the liver and the formation of energy increase. When beta2-adrenergic receptors are excited, the walls of blood vessels and the muscles of the bronchi relax, the synthesis of insulin is accelerated, and the breakdown of fat in the liver. Stimulation of beta-adrenergic receptors with the help of catecholamines mobilizes all the forces of the body.

Drugs from the group of beta-adrenergic blockers reduce the frequency, strength of heart contractions, reduce pressure, and reduce oxygen consumption by the heart. The mechanism of action of beta-blockers (BAB) is associated with the following functions:

1. Diastole lengthens - due to improved coronary perfusion, intracardiac diastolic pressure decreases.
2. The blood flow is redistributed from normally vascularized to ischemic areas, which increases exercise tolerance.
3. The antiarrhythmic effect consists in suppressing arrhythmogenic and cardiotoxic effects, preventing the accumulation of calcium ions in the heart cells, which can worsen the energy metabolism in the myocardium.

medicinal properties

Non-selective and cardioselective beta-blockers are able to inhibit one or more receptors. They have opposite vasoconstrictive, hypertensive, antiallergic, bronchodilator and hyperglycemic effects. When adrenaline binds to adrenoreceptors under the influence of adrenoblockers, stimulation occurs, sympathomimetic internal activity increases. Depending on the type of beta-blockers, their properties are distinguished:

1. Non-selective beta-1,2-blockers: reduce peripheral vascular resistance, myocardial contractility. Due to the drugs of this group, arrhythmia is prevented, the production of renin by the kidneys, and pressure are reduced. At the initial stages of treatment, vascular tone increases, but then it decreases to normal. Beta-1,2-blockers inhibit platelet aggregation, thrombus formation, increase myometrial contraction, and activate the motility of the digestive tract. In ischemic heart disease, adrenergic blockers improve exercise tolerance. In women, non-selective beta-blockers increase uterine contractility, reduce blood loss during childbirth or after surgery, lower intraocular pressure, which makes them suitable for glaucoma.
2. Selective (cardioselective) beta1-blockers - reduce the automatism of the sinus node, reduce the excitability and contractility of the heart muscle. They reduce myocardial oxygen demand, suppress the effects of norepinephrine and epinephrine under stress. Due to this, orthostatic tachycardia is prevented, and mortality in heart failure is reduced. This improves the quality of life of people with ischemia, dilated cardiomyopathy, after a stroke or heart attack. Beta1-blockers eliminate the narrowing of the capillary lumen, reduce the risk of developing bronchospasm in bronchial asthma, and eliminate the risk of hypoglycemia in diabetes mellitus.
3. Alpha and beta-blockers - lower cholesterol and triglyceride levels, normalize lipid profile indicators. Due to this, the blood vessels dilate, the afterload on the heart decreases, and the renal blood flow does not change. Alpha-beta-blockers improve myocardial contractility, help blood not to remain in the left ventricle after contraction, but to completely pass into the aorta. This leads to a reduction in the size of the heart, a decrease in the degree of its deformation. In heart failure, drugs reduce ischemic attacks, normalize the cardiac index, reduce mortality in coronary disease or dilated cardiomyopathy.

Classification

To understand the principle of operation of drugs, the classification of beta-blockers is useful. They are divided into non-selective, selective. Each group is divided into two more subspecies - with or without internal sympathomimetic activity. Thanks to such a complex classification, doctors have no doubts about the choice of the optimal medication for a particular patient.

By predominant action on beta-1 and beta-2-adrenergic receptors

By the type of influence on the types of receptors, selective beta-blockers and non-selective beta-blockers are distinguished. The former act only on cardiac receptors, so they are also called cardioselective. Non-selective drugs affect any receptor. Non-selective beta-1,2-blockers include Bopindolol, Metipranolol, Oxprenol, Sotalol, Timolol. Selective beta-1-blockers are Bisoprolol, Metoprolol, Atenolol, Tilinolol, Esmolol. Alpha-beta-blockers include Proxodalol, Carvedilol, Labetalol.

By ability to dissolve in lipids or water

Beta-blockers are divided into lipophilic, hydrophilic, lipohydrophilic. Fat-soluble are Metoprolol, Propranolol, Pindolol, Oxprenol, hydrophilic - Atenolol, Nadolol. Lipophilic drugs are well absorbed in the gastrointestinal tract and metabolized by the liver. In renal failure, they do not accumulate, therefore they undergo biotransformation. Lipohydrophilic or amphophilic preparations contain Acebutalol, Bisoprolol, Pindolol, Celiprolol.

Hydrophilic blockers of beta-adrenergic receptors are absorbed worse in the digestive tract, have a long half-life, and are excreted by the kidneys. They are preferred for use in patients with hepatic insufficiency because they are eliminated by the kidneys.

By generation

Among beta-blockers, medicines of the first, second and third generations are distinguished. The benefits of modern drugs are greater, their effectiveness is higher, and there are fewer harmful side effects. First-generation drugs include Propranolol (part of Anaprilin), Timolol, Pindolol, Sotalol, Alprenol. Means of the second generation - Atenolol, Bisoprolol (part of Concor), Metoprolol, Betaxolol (Lokren tablets).

Third-generation beta-blockers additionally have a vasodilatory effect (relax blood vessels), these include Nebivolol, Carvedilol, Labetalol. The first increases the production of nitric oxide, which regulates the relaxation of blood vessels. Carvedilol additionally blocks alpha-adrenergic receptors and increases the production of nitric oxide, and Labetalol acts on both alpha- and beta-adrenergic receptors.

List of beta blockers

Only a doctor can choose the right drug. He also prescribes the dosage and frequency of taking the medicine. List of known beta blockers:

1. Selective beta blockers

These funds act selectively on the receptors of the heart and blood vessels, therefore they are used only in cardiology.

1.1 No intrinsic sympathomimetic activity

1.2 With intrinsic sympathomimetic activity

2. Non-selective beta blockers

These medicines do not have a selective effect, they lower arterial and intraocular pressure.

2.1 No intrinsic sympathomimetic activity

2.2 With intrinsic sympathomimetic activity

3. Beta blockers with vasodilating properties

To solve the problems of high blood pressure, adrenoreceptor blockers with vasodilatory properties are used. They constrict blood vessels and normalize the work of the heart.

3.1 No intrinsic sympathomimetic activity

3.2 With intrinsic sympathomimetic activity

4. Long-acting BAB

Lipophilic beta-blockers - long-acting drugs work longer than antihypertensive analogues, therefore, they are prescribed at a lower dosage and at a reduced frequency. These include metoprolol, which is contained in the tablets Egilok Retard, Corvitol, Emzok.

5. Adrenoblockers of ultrashort action

Cardioselective beta-blockers - drugs of ultra-short action have a working time of up to half an hour. These include esmolol, which is found in Breviblok, Esmolol.

Indications for use

There are a number of pathological conditions that can be treated with beta-blockers. The decision on the appointment is made by the attending physician on the basis of the following diagnoses:

1. Angina pectoris and sinus tachycardia. Often, for the prevention of attacks and the treatment of angina pectoris, beta-blockers are the most effective means. The active substance accumulates in the tissues of the body, providing support to the heart muscle, which reduces the risk of recurrence of myocardial infarction. The ability of the drug to accumulate allows you to temporarily reduce the dose. The expediency of taking BAB in angina pectoris increases with the simultaneous presence of sinus tachycardia.
2. Myocardial infarction. The use of BAB in myocardial infarction leads to the limitation of the sector of necrosis of the heart muscle. This leads to reduced mortality, reduced risk of cardiac arrest and recurrence of myocardial infarction. It is recommended to use cardioselective agents. Application is permissible to begin immediately at the time of admission of the patient to the hospital. Duration - 1 year after myocardial infarction.
3. Heart failure. The prospects for the use of β-blockers for the treatment of heart failure are still under study. Currently, cardiologists allow the use of drugs if this diagnosis is combined with exertional angina, arterial hypertension, arrhythmia, tachysistological form of atrial fibrillation.
4. Arterial hypertension. Young people who lead an active lifestyle often experience hypertension. In these cases, according to the doctor's prescription, BAB can be prescribed. An additional indication for prescribing is the combination of the main diagnosis (hypertension) with rhythm disturbance, angina pectoris and after myocardial infarction. The development of hypertension into hypertension with left ventricular hypertrophy is the basis for taking BAB.
5. Heart rhythm abnormalities include such disorders as supraventricular arrhythmias, atrial flutter and fibrillation, sinus tachycardia. For the treatment of these conditions, drugs from the BAB group are successfully used. A less pronounced effect is observed in the treatment of ventricular arrhythmias. In combination with potassium agents, BAB is successfully used for the treatment of arrhythmias caused by glycoside intoxication.

Features of application and rules of admission

When the doctor decides on the appointment of beta-blockers, the patient must inform the doctor about the presence of such diagnoses as emphysema, bradycardia, asthma and arrhythmia. An important circumstance is pregnancy or suspicion of it. BAB are taken simultaneously with food or immediately after the meal, as food reduces the severity of side effects. Dosage, regimen and duration of therapy are determined by the attending cardiologist.

During treatment, it is recommended to carefully monitor the pulse. If the frequency drops below the established level (determined when prescribing a treatment regimen), it is required to inform the doctor about this. In addition, observation by a doctor during the course of taking the drugs is a condition for the effectiveness of therapy (a specialist, depending on individual indicators, can adjust the dosage). You can not stop taking BAB yourself, otherwise the side effects will be aggravated.

Side effects and contraindications of beta blockers

The appointment of BAB is contraindicated in hypotension and bradycardia, bronchial asthma, decompensated heart failure, cardiogenic shock, pulmonary edema, insulin-dependent diabetes mellitus. Relative contraindications include the following conditions:

• chronic form of obstructive pulmonary disease in the absence of bronchospastic activity;
• peripheral vascular diseases;
• transient lameness of the lower extremities.

Features of the impact of BAB on the human body can lead to a number of side effects of varying severity. Patients may experience the following:

• insomnia;
• weakness;
• headache;
• respiratory failure;
• exacerbation of coronary artery disease;
• bowel disorder;
• mitral valve prolapse;
• dizziness;
• depression;
• drowsiness;
• fatigue;
• hallucinations;
• nightmares;
• slowing down the reaction;
• anxiety;
• conjunctivitis;
• noise in ears;
• convulsions;
• phenomenon (pathology) Raynaud;
• bradycardia;
• psychoemotional disorders;
• oppression of bone marrow hematopoiesis;
• heart failure;
• heartbeat;
• hypotension;
• atrioventricular block;
• vasculitis;
• agranulocytosis;
• thrombocytopenia;
• muscle and joint pain
• chest pain;
• nausea and vomiting;
• violations of the liver;
• abdominal pain;
• flatulence;
• spasm of the larynx or bronchi;
• dyspnea;
• skin allergy (itching, redness, rash);
• cold extremities;
• sweating;
• baldness;
• muscle weakness;
• decreased libido;
• decrease or increase in the activity of enzymes, blood glucose and bilirubin levels;
• Peyronie's disease.

Withdrawal and how to avoid it

With long-term treatment with high dosages of BBs, a sudden stop of therapy can cause a withdrawal syndrome. Severe symptoms manifest as ventricular arrhythmias, angina pectoris, and myocardial infarction. Mild effects are expressed in the form of increased blood pressure and tachycardia. The withdrawal syndrome develops several days after the course of therapy. To eliminate this outcome, you must follow the rules:

1. It is necessary to stop taking BAB slowly, within 2 weeks, gradually lowering the dose of the next dose.
2. During the gradual withdrawal and after the complete cessation of intake, it is important to sharply reduce physical activity and increase the intake of nitrates (in consultation with the doctor) and other antiangial agents. During this period, it is important to limit the intake of drugs that reduce pressure.

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Beta-blockers - a class of drugs used in diseases of the cardiovascular system (hypertension, angina pectoris, myocardial infarction, heart rhythm disturbances and chronic heart failure) and others. Millions of people around the world are currently taking beta-blockers. The developer of this group of pharmacological agents revolutionized the treatment of heart disease. In modern practical medicine, beta-blockers have been used for several decades.

purpose

Adrenaline and other catecholamines play an indispensable role in the life of the human body. They are released into the blood and affect sensitive nerve endings - adrenoreceptors located in tissues and organs. And they, in turn, are divided into 2 types: beta-1 and beta-2-adrenergic receptors.

Beta-blockers block beta-1-adrenergic receptors, establishing protection of the heart muscle from the influence of catecholamines. As a result, the frequency of contractions of the heart muscle decreases, the risk of an attack of angina pectoris and cardiac arrhythmias decreases.

Beta-blockers lower blood pressure using several mechanisms of action at once:

• blockade of beta-1 receptors;
• depression of the central nervous system;
• decreased sympathetic tone;
• a decrease in the level of renin in the blood and a decrease in its secretion;
• decrease in the frequency and speed of heart contractions;
• decrease in cardiac output.

In atherosclerosis, beta-blockers can relieve pain and prevent the further development of the disease by improving heart rate and reducing left ventricular regression.

Together with beta-1, beta-2-adrenergic receptors are also blocked, which leads to negative side effects from the use of beta-blockers. Therefore, each drug in this group is assigned the so-called selectivity - the ability to block beta-1-adrenergic receptors without affecting beta-2-adrenergic receptors in any way. The higher the selectivity of the drug, the more effective its therapeutic effect.

Indications

The list of beta-blocker indications includes:

• heart attack and post-infarction condition;
• angina;
• heart failure;
• high blood pressure;
• hypertrophic cardiomyopathy;
• problems with heart rhythm;
• essential tremor;
• Marfan syndrome;
• migraine, glaucoma, anxiety and other diseases that are not of a cardiological nature.

Beta-blockers are very easy to recognize among other drugs by names with a characteristic “lol” ending. All drugs of this group have differences in the mechanisms of action on receptors and side effects. According to the main classification, beta-blockers are divided into 3 main groups.

I generation - non-cardioselective

Preparations of the first generation - non-cardioselective blockers - are among the earliest representatives of this group of medicines. They block receptors of the first and second types, thus providing both therapeutic and side effects (may lead to bronchospasm).

Some beta-blockers have the ability to partially stimulate beta-adrenergic receptors. This property is called intrinsic sympathomimetic activity. Such beta-blockers slow down the heart rate and the strength of its contractions to a lesser extent, have a lesser negative effect on lipid metabolism, and less often lead to the development of a withdrawal syndrome.

I generation drugs with internal sympathomimetic activity include:

• Alprenolol(Aptin);
• Bucindolol;
• Labetalol;
• Oxprenolol(Trazicor);
• Penbutolol(Betapressin, Levatol);
• Dilevalol;
• Pindolol(Whisken);
• Bopindolol(Sandorm);
• Karteolol.

• Nadolol(Korgard);
• Timolol(Blocardin);
• propranolol(Obzidan, Anaprilin);
• Sotalol(Sotahexal, Tenzol);
• Flestrolol;
• Nepradilol.

II generation - cardioselective

II generation drugs block predominantly type 1 receptors, the bulk of which are localized in the heart. Therefore, cardioselective beta-blockers have fewer side effects and are safe in the presence of concomitant pulmonary diseases. Their activity does not affect beta-2-adrenergic receptors located in the lungs.

Second-generation beta-blockers are usually included in the list of effective drugs prescribed for atrial fibrillation and sinus tachycardia.

With intrinsic sympathomimetic activity

• Talinolol(Cordanum);
• Acebutalol(Sektral, Acekor);
• Epanolol(Vasacor);
• Celiprolol.

No intrinsic sympathomimetic activity

• Atenolol(Betacard, Tenormin);
• Esmolol(Brevibrock);
• metoprolol(Serdol, Metokol, Metocard, Egilok, Metozok, Corvitol, Betalok zok, Betalok);
• bisoprolol(Coronal, Cordinorm, Tirez, Niperten, Corbis, Concor, Bisomor, Bisogamma, Biprol, Biol, Bidop, Aritel);
• Betaxolol(Kerlon, Lokren, Betak);
• Nebivolol(Nebilong, Nebilet, Nebilan, Nebikor, Nebivator, Binelol, Od-neb, Nevotens);
• Carvedilol(Talliton, Recardium, Coriol, Karvenal, Karvedigamma, Dilatrend, Vedikardol, Bagodilol, Acridilol);
• Betaxolol(Kerlon, Lokren, Betak).

III generation - with vasodilating properties

Third-generation beta-blockers have additional pharmacological properties, as they block not only beta receptors, but also alpha receptors located in the blood vessels.

Non-cardioselective

New generation non-selective beta-blockers are drugs that equally affect beta-1 and beta-2 adrenoreceptors and help to relax blood vessels.

• Pindolol;
• Nipradilol;
• medroxalol;
• Labetalol;
• Dilevalol;
• Bucindolol;
• Amozulalol.

Cardioselective

Third-generation cardioselective drugs increase the release of nitric oxide, which leads to vasodilation and a decrease in the risk of atherosclerotic plaques. The new generation of cardioselective blockers include:

• Carvedilol;
• Celiprolol;
• Nebivolol.

By duration of action

In addition, beta-blockers are classified according to the duration of their useful action into long-acting and ultra-short-acting drugs. Most often, the duration of the therapeutic effect depends on the biochemical composition of beta-blockers.

Long acting

Long-acting drugs are divided into:

• Lipophilic short-acting - dissolve well in fats, the liver is actively involved in their processing, act for several hours. They better overcome the barrier between the circulatory and nervous systems ( propranolol);
• Lipophilic long-acting ( Retard, Metoprolol).
• Hydrophilic - dissolve in water and are not processed in the liver ( Atenolol).
• Amphiphilic - have the ability to dissolve in water and fats ( Bisoprolol, Celiprolol, Acebutolol), has two routes of excretion from the body (renal excretion and hepatic metabolism).

Long-acting drugs differ in the mechanisms of action on adrenoreceptors and are divided into cardioselective and non-cardioselective.

Non-cardioselective

• Sotalol;
• Penbutolol;
• Nadolol;
• Bopindolol.

Cardioselective

• Epanolol;
• bisoprolol;
• Betaxolol;
• Atenolol.

Ultra short action

Ultra-short-acting beta-blockers are used only for droppers. The beneficial substances of the drug are destroyed under the influence of blood enzymes and stop 30 minutes after the end of the procedure.

The short duration of active action makes the drug less dangerous in concomitant diseases - hypotension and heart failure, and cardioselectivity - in broncho-obstructive syndrome. The representative of this group is the substance Esmolol.

Contraindications

Reception of beta-blockers is absolutely contraindicated in:

• pulmonary edema;
• cardiogenic shock;
• severe form of heart failure;
• bradycardia;
• chronic obstructive pulmonary disease;
• bronchial asthma;
• 2 degrees of atrioventricular heart block;
• hypotension (decrease in blood pressure by more than 20% of normal values);
• uncontrolled insulin-dependent diabetes mellitus;
• Raynaud's syndrome;
• atherosclerosis of peripheral arteries;
• manifestation of an allergy to the drug;
• pregnancy, as well as in childhood.

Side effects

The use of such drugs should be taken very seriously and carefully, because in addition to the therapeutic effect, they have the following side effects.

• Overwork, sleep disturbances, depression;
• headache, dizziness;
• memory impairment;
• Rash, itching, symptoms of psoriasis;
• Hair loss;
• Stomatitis;
• Poor exercise tolerance, rapid fatigue;
• Worsening of the course of allergic reactions;
• Violation of the heart rhythm - a decrease in the frequency of heart contractions;
• Heart blockade, provoked by a violation of the function of the conduction of the heart;
• Decreased blood sugar levels;
• Lowering the level of cholesterol in the blood;
• Exacerbation of diseases of the respiratory system and bronchospasm;
• The occurrence of a heart attack;
• The risk of a sharp increase in pressure after stopping the drug;
• The occurrence of sexual dysfunction.

An important role in the regulation of body functions have catecholamines: adrenaline and norepinephrine. They are released into the blood and act on special sensitive nerve endings - adrenoreceptors. The latter are divided into two large groups: alpha and beta adrenoreceptors. Beta-adrenergic receptors are located in many organs and tissues and are divided into two subgroups.

With the activation of β1-adrenergic receptors, the frequency and strength of heart contractions increase, the coronary arteries expand, the conductivity and automatism of the heart improve, the breakdown of glycogen in the liver and the formation of energy increase.

When β2-adrenergic receptors are excited, the walls of blood vessels, the muscles of the bronchi relax, the tone of the uterus decreases during pregnancy, the secretion of insulin and the breakdown of fat increase. Thus, stimulation of beta-adrenergic receptors with the help of catecholamines leads to the mobilization of all the forces of the body for active life.

Beta-blockers (BABs) are a group of drugs that bind beta-adrenergic receptors and prevent the action of catecholamines on them. These drugs are widely used in cardiology.

BAB reduce the frequency and strength of heart contractions, lower blood pressure. As a result, oxygen consumption by the heart muscle decreases.

Diastole is lengthened - a period of rest, relaxation of the heart muscle, during which the coronary vessels are filled with blood. The improvement of coronary perfusion (myocardial blood supply) is also facilitated by a decrease in intracardiac diastolic pressure.

There is a redistribution of blood flow from normally vascularized areas to ischemic areas, as a result of which exercise tolerance improves.

BABs have antiarrhythmic activity. They suppress the cardiotoxic and arrhythmogenic effects of catecholamines, and also prevent the accumulation of calcium ions in the heart cells, which impair energy metabolism in the myocardium.

Classification

BAB is an extensive group of medicines. They can be classified in many ways.
Cardioselectivity - the ability of the drug to block only β1-adrenergic receptors, without affecting β2-adrenergic receptors, which are located in the wall of the bronchi, blood vessels, uterus. The higher the selectivity of BAB, the safer it is to use it in concomitant diseases of the respiratory tract and peripheral vessels, as well as in diabetes mellitus. However, selectivity is a relative concept. When prescribing the drug in large doses, the degree of selectivity decreases.

Some BABs have intrinsic sympathomimetic activity: the ability to stimulate beta-adrenergic receptors to some extent. Compared to conventional β-blockers, such drugs slow down the heart rate and the strength of its contractions less, less often lead to the development of withdrawal syndrome, and have less negative effect on lipid metabolism.

Some BABs are able to additionally dilate blood vessels, that is, they have vasodilating properties. This mechanism is realized with the help of pronounced internal sympathomimetic activity, blockade of alpha-adrenergic receptors, or direct action on the vascular walls.

The duration of action most often depends on the characteristics of the chemical structure of the BAB. Lipophilic agents (propranolol) act for several hours and are quickly excreted from the body. Hydrophilic drugs (atenolol) are effective for a longer time, may be prescribed less frequently. At present, long-acting lipophilic substances (metoprolol retard) have also been created. In addition, there are BAB with a very short duration of action - up to 30 minutes (esmolol).

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1. Non-cardioselective BBs:

BUT. Without intrinsic sympathomimetic activity:

• propranolol (anaprilin, obzidan);
• nadolol (korgard);
• sotalol (sotahexal, tensol);
• timolol (blockarden);
• nipradilol;
• flestrolol.

• oxprenolol (trazicor);
• pindolol (whisken);
• alprenolol (aptin);
• penbutolol (betapressin, levatol);
• bopindolol (Sandorm);
• bucindolol;
• dilevalol;
• carteolol;
• labetalol.

2. Cardioselective BBs:

A. Without internal sympathomimetic activity:

B. With internal sympathomimetic activity:

• acebutalol (acecor, sectral);
• talinolol (cordanum);
• celiprolol;
• epanolol (vasacor).

3. BAB with vasodilating properties:

A. Non-cardioselective:

B. Cardioselective:

• carvedilol;
• nebivolol;
• celiprolol.

4. BAB long-acting:

A. Non-cardioselective:

• bopindolol;
• nadolol;
• penbutolol;
• sotalol.

B.
Cardioselective:

• atenolol;
• betaxolol;
• bisoprolol;
• epanolol.

5. BAB of ultrashort action, cardioselective:

• esmolol.

Use in diseases of the cardiovascular system

angina pectoris

In many cases, BBs are among the leading agents for the treatment and prevention of seizures. Unlike nitrates, these drugs do not cause tolerance (drug resistance) with long-term use. BAB are able to accumulate (accumulate) in the body, which allows you to reduce the dosage of the drug after a while. In addition, these drugs protect the heart muscle itself, improving prognosis by reducing the risk of recurrent myocardial infarction.

The antianginal activity of all BABs is approximately the same.
Their choice is based on the duration of the effect, the severity of side effects, cost and other factors.

Begin treatment with a small dose, gradually increasing it to an effective one. The dosage is selected in such a way that the heart rate at rest is not less than 50 per minute, and the level of systolic blood pressure is not less than 100 mm Hg. Art. After the onset of the therapeutic effect (cessation of angina attacks, improvement in exercise tolerance), the dose is gradually reduced to the minimum effective.

Long-term use of high doses of BAB is not advisable, as this significantly increases the risk of side effects. With insufficient effectiveness of these drugs, it is better to combine them with other groups of drugs.

BAB should not be abruptly canceled, as this may cause a withdrawal syndrome.

BABs are especially indicated if exertional angina is combined with sinus tachycardia, glaucoma, constipation, and gastroesophageal reflux.

myocardial infarction

Early use of BAB helps to limit the zone of necrosis of the heart muscle. This reduces mortality, reduces the risk of recurrent myocardial infarction and cardiac arrest.

Such an effect is exerted by BAB without internal sympathomimetic activity, it is preferable to use cardioselective agents. They are especially useful when myocardial infarction is combined with arterial hypertension, sinus tachycardia, postinfarction angina and tachysystolic form.

BAB can be prescribed immediately upon admission of the patient to the hospital to all patients in the absence of contraindications. In the absence of side effects, their treatment continues for at least a year after myocardial infarction.

Chronic heart failure

The use of BBs in heart failure is being studied. It is believed that they can be used in a combination of heart failure (especially diastolic) and angina pectoris. Rhythm disturbances, arterial hypertension, tachysystolic form of atrial fibrillation in combination with are also grounds for prescribing this group of drugs.

Hypertonic disease

BAB are indicated in the treatment of complicated hypertension. They are also widely used in young patients with an active lifestyle. This group of drugs is prescribed for a combination of arterial hypertension with angina pectoris or cardiac arrhythmias, as well as after a myocardial infarction.

Heart rhythm disorders

BAB are used for such heart rhythm disorders as atrial fibrillation and flutter, supraventricular arrhythmias, poorly tolerated sinus tachycardia. They can also be prescribed for ventricular arrhythmias, but their effectiveness in this case is usually less pronounced. BAB in combination with potassium preparations are used for the treatment caused by glycoside intoxication.

Side effects

The cardiovascular system

BABs inhibit the ability of the sinus node to generate impulses that cause heart contractions and cause sinus bradycardia - a slowing of the pulse to values ​​less than 50 per minute. This side effect is much less pronounced in BAB with internal sympathomimetic activity.

Drugs in this group can cause atrioventricular blockade of varying degrees. They also reduce the force of heart contractions. The latter side effect is less pronounced in BABs with vasodilatory properties. BBs lower blood pressure.

Medicines of this group cause spasm of peripheral vessels. A cold snap of the extremities may appear, the course of Raynaud's syndrome worsens. These side effects are almost devoid of drugs with vasodilating properties.

BAB reduce renal blood flow (except for nadolol). Due to the deterioration of the peripheral circulation in the treatment of these drugs, there is sometimes a pronounced general weakness.

Respiratory system

BAB cause bronchospasm due to concomitant blockade of β2-adrenergic receptors. This side effect is less pronounced in cardioselective agents. However, their effective doses for angina or hypertension are often quite high, while cardioselectivity is significantly reduced.
The use of high doses of BAB can provoke apnea, or a temporary cessation of breathing.

BAB worsen the course of allergic reactions to insect bites, drug and food allergens.

Nervous system

Propranolol, metoprolol and other lipophilic BABs penetrate from the blood into brain cells through the blood-brain barrier. Therefore, they can cause headaches, sleep disturbances, dizziness, memory impairment and depression. In severe cases, hallucinations, convulsions, coma occur. These side effects are much less pronounced in hydrophilic BBs, in particular, atenolol.

Treatment with BAB may be accompanied by impaired neuromuscular conduction. This leads to muscle weakness, reduced stamina and fatigue.

Metabolism

Non-selective β-blockers inhibit the production of insulin in the pancreas. On the other hand, these drugs inhibit the mobilization of glucose from the liver, contributing to the development of prolonged hypoglycemia in patients with diabetes mellitus. Hypoglycemia promotes the release of adrenaline into the blood, acting on alpha-adrenergic receptors. This leads to a significant rise in blood pressure.

Therefore, if it is necessary to prescribe BAB to patients with concomitant diabetes mellitus, cardioselective drugs should be preferred or replaced with calcium antagonists or agents of other groups.

Many BBs, especially non-selective ones, reduce the blood levels of “good” cholesterol (high density alpha lipoproteins) and increase the level of “bad” cholesterol (triglycerides and very low density lipoproteins). Drugs with β1-internal sympathomimetic and α-blocking activity (carvedilol, labetolol, pindolol, dilevalol, celiprolol) are deprived of this disadvantage.

Other side effects

Treatment of BAB in some cases is accompanied by sexual dysfunction: erectile dysfunction and loss of sexual desire. The mechanism of this effect is unclear.

BAB can cause skin changes: rash, itching, erythema, psoriasis symptoms. In rare cases, hair loss and stomatitis are recorded.

One of the serious side effects is the inhibition of hematopoiesis with the development of agranulocytosis and thrombocytopenic purpura.

withdrawal syndrome

If BAB are used for a long time at a high dosage, then the sudden cessation of treatment can provoke the so-called withdrawal syndrome. It is manifested by an increase in angina attacks, the occurrence of ventricular arrhythmias, and the development of myocardial infarction. In milder cases, the withdrawal syndrome is accompanied by tachycardia and increased blood pressure. The withdrawal syndrome usually appears a few days after stopping taking the beta-blocker.

To avoid the development of withdrawal syndrome, the following rules must be observed:

• cancel BAB slowly, within two weeks, gradually reducing the dosage by one dose;
• during and after the withdrawal of BAB, it is necessary to limit physical activity, if necessary, increase the dosage of nitrates and other antianginal drugs, as well as drugs that reduce blood pressure.

Contraindications

BAB is absolutely contraindicated in the following situations:

• pulmonary edema and cardiogenic shock;
• severe heart failure;
• bronchial asthma;
• atrioventricular block II - III degree;
• systolic blood pressure level 100 mm Hg. Art. and below;
• heart rate less than 50 per minute;
• poorly controlled insulin-dependent diabetes mellitus.

A relative contraindication to the appointment of BAB is Raynaud's syndrome and atherosclerosis of peripheral arteries with the development of intermittent claudication.