Each drug belongs to a specific pharmacological group. This means that some medicines have the same mechanism of action, indications for use and side effects. One of the major pharmacological groups is beta-adrenergic agonists. These drugs are widely used in the treatment of respiratory and cardiovascular pathologies.
What are B-adrenergic agonists?
Beta-adrenergic agonists are a group of medical products 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-adrenergic agonists bind to receptors, the production of biological substances such as dopamine and adrenaline is stimulated. Another name for these compounds is beta agonists. Their main effects are increased heart rate, increased blood pressure and improved bronchial conduction.
Beta-adrenergic agonists: action in the body
Beta agonists are divided into B1 and B2 adrenergic agonists. Receptors for these substances are located in the internal organs. When binding with them, beta-adrenergic 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.
- Acceleration of lipolysis. When using B1-adrenergic agonists, free fatty acids appear in the blood, which are the products of the breakdown of triglycerides.
- High blood pressure. This action is due to the stimulation of the renin-angiotensin-aldosterone system (RAAS).
The listed changes in the body are caused by the binding of adrenergic agonists to B1 receptors. They are located in the heart muscle, blood vessels, adipose tissue and juxtaglomerular apparatus of the kidney cells.
B2 receptors are located in the bronchi, uterus, skeletal muscles, and the central nervous system. In addition, they are found in the heart and blood vessels. Beta-2-adrenergic agonists cause the following effects:
- Improving bronchial conduction. This action is due to the relaxation of smooth muscles.
- Acceleration of glycogenolysis in the muscles. As a result, skeletal muscles contract faster and stronger.
- Relaxation of the myometrium.
- Acceleration of glycogenolysis in liver cells. This leads to an increase in blood sugar.
- Increased heart rate.
What drugs belong to the group of B-adrenergic agonists?
Doctors often prescribe beta-adrenergic agonists. Drugs belonging to this pharmacological group are divided into short- and fast-acting drugs. In addition, drugs are released that have a selective effect only on certain organs. Some drugs act immediately on the B1 and B2 receptors. The most famous medicines from the group of beta-adrenergic agonists are the medicines “Salbutamol”, “Fenoterol”, “Dopamine”. B-agonists are used in the treatment of pulmonological and cardiological diseases. Also, some of them are used in the intensive care unit (medication "Dobutamine"). Less commonly, drugs of this group are used in gynecological practice.
Classification of beta-adrenergic agonists: varieties of medicines
Beta-adrenergic agonists are a pharmacological group that includes a large number of medicines. Therefore, they are divided into several groups. The classification of b-agonists includes:
- Non-selective beta-adrenergic agonists. This group includes medications Orciprenaline and Isoprenaline.
- Selective B1-adrenergic agonists. They are used in cardiology and resuscitation departments. Representatives of this group are the drugs "Dobutamine" and "Dopamine."
- Selective beta-2-adrenergic agonists. This group includes medications 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. The first group includes medicines “Fenoterol”, “Terbutaline”, “Salbutamol” and “Hexoprenaline”. Long-acting drugs are Formoterol, Salmeterol and Indacaterol drugs.
Indications for the use of B-adrenergic agonists
Indications for the use of B-adrenergic 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 rhythm disturbances, worsening cardiac conduction, bronchial asthma. Now doctors 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, since they affect only certain organs.
Indications for the appointment of B1-adrenergic agonists:
- Acute heart failure.
- The shock of any etiology.
- Collapse.
- Decompensated heart defects.
- Rarely, severe coronary heart 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 medicine “Fenoterol” is used in gynecological practice to slow down labor and prevent miscarriage. In this case, the drug is administered intravenously.
In what cases are B-adrenomimetics contraindicated?
It should be remembered that the drugs of the beta-adrenergic agonist group have a number of contraindications 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 extremities, cardiac arrhythmias, excitement 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 can not be used with cardiac tamponade.
B2 agonists are contraindicated in the following cases:
- Intolerance to beta-adrenergic agonists.
- Pregnancy complicated by bleeding, placental abruption, threatened abortion.
- Children under 2 years old.
- Inflammatory processes in the myocardium, rhythm disturbances.
- Diabetes.
- Aortic stenosis.
- Arterial hypertension.
- Acute heart failure.
- Thyrotoxicosis.
The drug "Salbutamol": instructions for use
The drug "Salbutamol" refers to short-acting B2 agonists. It is used for bronchial obstruction syndrome. Most often used in aerosols at a dose of 1-2 (0.1-0.2 mg). Children are preferably inhaled through a nebulizer. There is also a tablet form of the drug. The dosage for adults is 6-16 mg per day.
Salbutamol: the price of a drug
The medication is used as monotherapy for mild bronchial asthma. If the patient has a moderate or severe stage of the disease, prolonged drugs are used (long-acting beta-adrenergic agonists). They are the basic therapy for bronchial asthma. To quickly stop the attack of suffocation, use the drug "Salbutamol". The price of the medicine is from 50 to 160 rubles, depending on the manufacturer and the dose contained in the bottle.