Alpha-blockers are represented by a large and heterogeneous group of drugs. In the seventies, interest in these medicines decreased significantly due to the fact that specialists began to use thiazide diuretics, ACE inhibitors to treat hypertension. By the beginning of the nineties, it was found that alpha 1-blockers selective long-term exposure (mainly, the drug "Doxazosin") are comparable in tolerance, safety, antihypertensive activity with other drugs, the action of which is aimed at lowering blood pressure. In addition, additional properties were discovered in the medicines that made it possible to prescribe them to patients with diabetes mellitus, benign prostatic hyperplasia, dyslipidemia, disorders in the male genital area, as well as obliterating endoarteritis.
Alpha blockers. Classification
The drugs are divided into two main categories: selective and non-selective.
The group of non-selective agents includes alpha 1- and 2-blockers (for example, the drug "Fetolamine").
Such medicines as “Terazozin”, “Doxazosin”, “Prazosin” are considered selective. Preparations of this category mainly affect receptors that are located in the smooth muscles of the prostate, the neck of the bladder, as well as the prostatic urethra.
Some antihypertensive drugs belonging to other groups of drugs exhibit the same properties as alpha-blockers. Such drugs, in particular, include the drug "Carvedilol."
There are also drugs whose properties are similar to those shown by both beta and alpha-blockers. Such medicines, in addition, have antioxidant properties. The mechanism of their effect is to compete with catecholamines. The fight is carried out for peripheral adrenergic receptors alpha 1 and beta-adrenergic receptors. With prolonged use, the degree of exposure to these drugs begins to weaken, and after a few months completely disappears.
Alpha blockers have a lot of advantages. In particular, they have a beneficial effect on the level of triglycerides and cholesterol in blood plasma. This significantly reduces the risk of developing atherosclerosis. The drugs do not affect the concentration of sugar in the blood, lower blood pressure without increasing the heart rate. In addition, these drugs do not affect the state of potency.
Alpha-blockers have few side effects. The most significant is the "effect of the first dose."
It should be said that alpha-blockers have the ability to expand both small and fairly large blood vessels. In this regard, the decrease in pressure is most clearly manifested in the vertical position of the patient, and less clearly in the horizontal. When a person (normal) rises from bed, the nervous system increases arterial tone. This is necessary to adapt the body to a vertical position. Acceptance of alpha 1-blockers prevents this device. When a person takes a vertical position, a sharp decrease in pressure occurs. As a result, the brain does not receive enough oxygen. A person begins to get dark in his eyes, dizzy, a sharp weakness may occur, in some cases the patient may faint. After passing out (taking a horizontal position), an improvement in the blood supply to the brain occurs. As a result, consciousness soon returns to the patient. Such a swoon, in fact, in itself does not pose a great danger. However, during the fall, there is a chance that the patient may get a dangerous injury.