Each drug belongs to a specific pharmacological group. This means that some drugs have the same mechanism of action, indications for use and side effects. One of the major pharmacological groups is beta-agonists. These drugs are widely used in the treatment of respiratory and cardiovascular pathologies.
What are B-agonists?
Beta-agonists are a group of medicines that are used in the treatment of various diseases. In the body, they bind to specific receptors located in the smooth muscles of the bronchi, uterus, heart, and vascular tissue. This interaction causes stimulation of beta cells. As a result, various physiological processes are activated. When B-agonists bind to receptors, the production of such biological substances as dopamine and adrenaline is stimulated. Another name for these compounds is beta-agonists. Their main effects are an increase in heart rate, an increase in blood pressure and an improvement in bronchial conduction.
Betaadrenomimetics: action in the body
Beta-agonists are divided into B1- and B2-agonists. Receptors for these substances are located in the internal organs. When bound to them, beta-agonists lead to the activation of many processes in the body. The following effects of B-agonists are distinguished:
- Increased cardiac automatism and improved conduction.
- Increased heart rate.
- Accelerating lipolysis. With the use of B1-agonists, free fatty acids appear in the blood, which are products of the breakdown of triglycerides.
- Increased blood pressure. This action is due to stimulation of the renin-angiotensin-aldosterone system (RAAS).
The binding of adrenomimetics to B1 receptors leads to the listed changes in the body. They are located in the heart muscle, blood vessels, adipose tissue and juxtaglomerular apparatus of kidney cells.
B2-receptors are found in the bronchi, uterus, skeletal muscles, central nervous system. In addition, they are found in the heart and blood vessels. Beta-2-agonists cause the following effects:
- Improvement of bronchial conduction. This action is due to the relaxation of smooth muscles.
- Acceleration of glycogenolysis in muscles. As a result, the skeletal muscles contract faster and stronger.
- Relaxation of the myometrium.
- Acceleration of glycogenolysis in liver cells. This leads to an increase in blood sugar levels.
- Increased heart rate.
Which drugs belong to the group of B-agonists?
Doctors often prescribe beta-agonists. Drugs belonging to this pharmacological group are divided into short-acting and fast-acting medicines. In addition, drugs are isolated that have a selective effect only on certain organs. Some drugs act directly on the B1 and B2 receptors. The most well-known medicines from the group of beta-agonists are the drugs Salbutamol, Fenoterol, Dopamine. B-agonists are used in the treatment of pulmonary and cardiac diseases. Also, some of them are used in the intensive care unit (drug "Dobutamine"). Less commonly, drugs of this group are used in gynecological practice.
Classification of beta-agonists: types of drugs
Beta-agonists are a pharmacological group that includes a large number of drugs. Therefore, they are divided into several groups. The classification of B-agonists includes:
- Non-selective beta-agonists. This group includes medicines "Orciprenaline" and "Isoprenaline".
- Selective B1-agonists. They are used in cardiology and intensive care units. Representatives of this group are the drugs Dobutamine and Dopamine.
- Selective beta-2-agonists. This group includes medicines used for diseases of the respiratory system. In turn, selective B2-agonists are divided into short-acting drugs and drugs that have a long-term effect. Effect. The first group includes medicines "Fenoterol", "Terbutalin", "Salbutamol" and "Hexoprenaline". Long-acting drugs are the drugs Formoterol, Salmeterol and Indacaterol.
Indications for the use of B-agonists
Indications for the use of B-agonists depend on the type of drug. Non-selective beta-agonists are currently practically not used. Previously, they were used to treat certain types of arrhythmias, deterioration of cardiac conduction, and bronchial asthma. Doctors now prefer to prescribe selective B-agonists. Their advantage is that they have far fewer side effects. In addition, selective drugs are more convenient to use, as they only affect certain organs.
Indications for the appointment of B1-agonists:
- Acute heart failure.
- Shock of any etiology.
- Collapse.
- Decompensated heart defects.
- Rare - severe coronary artery disease.
B2-agonists are prescribed for bronchial asthma, chronic obstructive pulmonary disease. In most cases, these drugs are used in the form of aerosols. Sometimes the drug "Fenoterol" is used in gynecological practice to slow down labor and prevent miscarriage. In this case, the drug is administered intravenously.
When are B-agonists contraindicated?
It should be remembered that drugs of the beta-agonist group have a number ofcontraindications and side effects. This is especially true for non-selective B-agonists. Side effects of these medications are the development of hyperglycemia, tremor of the limbs, heart rhythm disturbances, excitation of the central nervous system, etc. Beta-1-agonists are potent drugs, therefore they are used only in cases of urgent need. They are contraindicated in patients with a history of such pathologies: ventricular arrhythmia, subaortic stenosis, pheochromocytoma. Also, they should not be used for cardiac tamponade.
B2 agonists are contraindicated in the following cases:
- Intolerance to beta-agonists.
- Pregnancy complicated by bleeding, placental abruption, threatened miscarriage.
- Children under 2 years old.
- Inflammatory processes in the myocardium, rhythm disturbances.
- Diabetes mellitus.
- Aortic stenosis.
- Hypertension.
- Acute heart failure.
- Thyrotoxicosis.
Medication "Salbutamol": instructions for use
Salbutamol is a short-acting B2 agonist. It is used for bronchial obstruction syndrome. Most often used in aerosols, 1-2 doses (0.1-0.2 mg). It is preferable for children to inhale through a nebulizer. There is also a tablet form of the drug. The dosage for adults is 6-16 mg per day.
Salbutamol: drug price
The drug is used as monotherapy formild bronchial asthma. If the patient has an average or severe stage of the disease, prolonged medications (long-acting beta-agonists) are used. They are the basic therapy for bronchial asthma. For quick relief of an asthma attack, the drug "Salbutamol" is used. The price of the drug is from 50 to 160 rubles, depending on the manufacturer and the dose contained in the vial.
