Alpha-blockers: description and classification

Thanks to scientific research in the field of pharmaceutics, the effect of medicines, the release of more modern highly effective medicines is constantly being studied. But there are a wide range of drugs that remain indispensable for decades. These include alpha-blockers.

Most often they are used in the medical treatment of hypertensive diseases, to reduce blood pressure, as well as a number of urological diseases, for example, chronic prostatitis and a benign prostatic tumor.

History of the discovery

The discovery of alpha-blockers in Russian pharmaceuticals was made in 1976. From that moment they were considered effective drugs reducing blood pressure. But their use is not always appropriate due to too many side effects. One of the first drugs of this group was Prazozin. Further, the release of other alpha-blockers, such as Doxasosin and Terarazine, was established. All of them, as well as Prazozin, are used to treat hypertensive disease, but differ from it by a more prolonged action.

But alpha-blockers also differ in degree, location and functional purpose. The drugs will be presented below.

Kinds

Adrenoreceptors are divided into two subspecies:

• Alpha-1 receptors that are localized on the surface of the postsynaptic membrane of the neuron, responsible for signals performed using catecholamines to address other neurons or effector cells, including some vascular cells. The consequence of the activity of such receptors is vasoconstriction.
• The alpha-2 receptors, which are located on the surface of the presynaptic membrane of the neuron, control the production of norepinephrine into the synaptic gap through negative feedback, thereby reducing the production of norepinephrine accumulated in the synaptic cleft.

The blockade of the alpha-1 receptors of smooth muscle vessels eliminates vasoconstriction, provoked by catecholamines. In turn, the alpha-2 receptors located on the presynaptic membrane of the neuron are not blocked, which means that there is an integrity of the feedback mechanism that provokes the release of norepinephrine.

Selective 1 (adrenoblockers) are antagonists of postsynaptic receptors. Such drugs eliminate the activity of receptors due to the effects of catecholamines in circulation and released by neurons.

Functions

In addition to the impact on lowering blood pressure, alpha-blockers (the drugs are listed below) have other functions. These are cardiac, metabolic, extracardiac therapeutic effects. Scientifically proven high efficacy of drugs to this group in the treatment of changes in the myocardium, coronary system, in the impact on proteins in the prostate.

Extracardiac

• Stimulation of kidney function.
• Purification of the bronchi.
• Improvement of metabolic processes in the genitourinary system with a benign prostatic tumor.

Alpha-blockers have a positive effect on reducing tumor growth and severity of impotence.

Cardiac

• Reduction of myocardial hypertrophy.
• Adjust the heart rate.

With caution because of the negative effect used for heart failure and angina.

Metabolic

• Reduce the risk of cholesteric plaque formation.
• Reduce the level of sugar (insulin) in the blood.

As mentioned above, alpha-blockers are often used to treat prostate diseases in men.

The male population over the age of 50 often suffers from this type of disease, the first place among which is prostatitis and prostate adenoma.

These diseases have a very negative impact on the lifestyle of a person as a whole. Constant problems with urination, discomfort, progressive impotence have certain difficulties for men of any age. In addition, the above diseases are considered to be rapidly developing. Often not without surgical intervention. To stop the acute phase of the disease, medications are used.

For drug intervention, a-blockers, inhibitors of 5-alpha-reductase are used.

Scheme of therapeutic action of inhibitors

The proliferation of muscle tissue of the prostate gland is provoked primarily by the hormonal background. Steroid 5-alpha-reductase stimulates the conversion of the hormone testosterone into dihydrotestosterone in the prostate cavity. The latter in turn comes into contact with the nuclear androgen receptor in the prostate and provokes the secretion of paracrine growth factors, they also move into the prostate. Alpha-blockers inhibitors of 5-alpha-reductase are able to help in this situation.

Excessive production of dihydrotestosterone causes a number of severe diseases, such as benign prostate tumor, oncological neoplasms, and other urological diseases of the prostate. At such a time, 5 alpha-reductase inhibitors are used as a medicinal treatment course. Their therapeutic effect is a blockade of reductase, which in turn lowers the level of dihydrotestosterone, which provokes diffuse changes in the prostate.

The most popular drugs of this group are Finasteride and Dutasteride. They have a similar therapeutic effect, differ in the time of exposure and the pattern of administration.

Blockers inhibitors of 5-alpha-reductase can be purchased at a pharmacy on prescription.

But despite the high efficiency, the drugs are used with caution and not in all cases because of the large number of negative manifestations and contraindications.

The main side effects of admission

• After using drugs to lower blood pressure, there is a possibility of hypotension.
• Nausea, headaches, dizziness.
• Heart palpitations, shortness of breath.
• Muscle pain, weakness.
• Sedation effect.
• Fluid retention, swelling.
• Pain in the stomach and intestines.
• Difficulty breathing through the nose, thirst.
• More often in the female half of the population there is a stimulation of the bladder, frequent urge to urinate.

Therefore, alpha-beta-blockers should be taken with caution.

One of the most serious consequences is postural hypotension, which can occur already with a single dose of the drug. Its first signs appear after half an hour or an hour after taking the medication. Mostly it concerns "Prazozin". To prevent this side effect, it is necessary to prescribe the drug according to the growing intake schedule and preferably at night.

In connection with the above side effects, alpha-blockers are prescribed in combination with diuretics to prevent fluid retention and anesthetics to relieve pain symptoms.

Medications of this group are prescribed as an independent therapy, and simultaneously with other medications for the treatment of various diseases.

Diseases

A number of diseases for which alpha-blockers are used:

• In the fight against hypertension in complex therapy, as a means to achieve an accelerated therapeutic effect.
• Benign formation in the prostate gland.
• Diabetes.
• Pheochromocytoma.
• Malignant neoplasm in the prostate gland.

Contraindications

In what cases are not prescribed alpha and beta blockers?

The main contraindications for taking medications are:

• Low blood pressure;
• dehydration;
• Therapy with the use of diuretics;
• Various heart defects;
• Chronic heart failure;
• bronchial asthma;
• Disturbance of heart rhythms.

Do not prescribe drugs of this kind when carrying the fetus and during lactation, as there are no precise laboratory studies on this issue.

Alpha-blockers in adenoma

The main drugs of this group, used to treat adenoma:

• "Uroksataral."
• "Cardura."
• "Gitrin".
• Rapaplo.
• Flomax.

The basis of these drugs is alpha-blockers. The list goes on.

Mechanism of action

The mechanism of action of such drugs in the fight against adenoma is simple, they relieve the tone of the muscles of the prostate and bladder, thereby contributing to the relief of urination.

Prescribe such medications with a course of treatment with an individual dosage, taken once or twice a day.

Prescribe medicines to categories of patients with advanced disease, who have difficulty urinating, and weaker drugs have not had the proper effect.

The main therapeutic effect begins to appear after a week of taking medications. After 14-21 days, there is a significant relief of the patient's condition.

special instructions

For a high therapeutic effect, alpha-blockers and 5-alpha-reductase inhibitors are taken in pairs. Data on the high effectiveness of the use of paired preparations are obtained as a result of medical clinical studies.

It is not recommended to combine the aforementioned medications together with drugs or dietary supplements from impotence. Can enhance the therapeutic effect of blockers, which is undesirable. The consequence may be a sharp drop in blood pressure.

Another negative consequence of taking alpha blockers for the treatment of urological diseases can be ejaculation in the bladder cavity. This does not cause negative consequences for the overall health.

When using medicines of this group for the control of adenoma, it is recommended to use other medicines to lower blood pressure. Accepted as an element of complex therapy, they may be less effective in treating hypertension.

For patients who do not suffer from hypertensive illnesses in the fight against changes in the prostate gland of alpha-blockers, it is recommended to constantly monitor the level of blood pressure.

Precautions for taking medications

• Medicines containing alpha blockers should be used solely for the purpose of the attending physician. The doctor should determine the dosage, the duration of the reception.
• Treatment with the use of such drugs should be carried out under the supervision of a doctor or within the walls of a medical institution.
• If side effects occur, stop taking the medication and consult a doctor.
• Do not change the dosage in the direction of increase by yourself.
• Admission of other drugs simultaneously with alpha-blockers should be agreed with the attending physician.
• Do not use alpha-blockers as an emergency therapy for hypertension without consulting with a doctor.
• Do not take overdue drugs or with broken packaging, damage to the hard shell of the tablets.
• Acquire drugs exclusively in licensed pharmacies.
• When taking medications of the above-mentioned group, constantly during the day and before bedtime, measure the blood pressure level.
• Taking medications with high blood pressure during pregnancy must be agreed with the doctor.

It is important to understand that an overdose of such drugs can lead to undesirable consequences.