Alpha-adrenergic receptor inhibitors (alpha-blockers) are used in the treatment of high blood pressure. They relax the smooth muscles of blood vessels, which leads to a decrease in systolic and diastolic pressure. What other advantages do alpha-blockers have? Find out if there are contraindications to the use of alpha-blockers and what they can cause side effects.

Contents:

  1. Alpha-blockers - application
  2. Alpha-blockers - mechanism of action
  3. Alpha blockers - division
  4. Alpha-blockers - advantages
  5. Alpha-blockers and benign prostatic hyperplasia
  6. Alpha-blockers - side effects
  7. Alpha-blockers - contraindications for use

Alpha-adrenergic receptor inhibitors (alpha-blockers)are especially recommended for hypertensive patients with prostate hyperplasia. This is because these drugs also block alpha receptors at the mouth of the bladder. This causes the muscles to relax, making it easier to urinate.

Alpha-adrenoreceptor inhibitors are usually well tolerated by the patient's body. They can cause an excessive drop in blood pressure, which is characteristic of most antihypertensive drugs. The effect of their operation depends on the individual predispositions of the patient.

Sometimes prescribed medication may not be effective. Therefore, it is advisable to measure blood pressure regularly while using alpha-blockers. If the results are too low or too high, you should urgently consult your doctor. You should never discontinue hypertension medications on your own, contrary to the advice of a specialist.

Alpha-blockers - application

Alpha-blockers are used to treat:

  • hypertension
  • benign prostatic hyperplasia
  • Raynaud's disease
  • congestive heart failure (CHF)
  • pheochromocytoma
  • erectile dysfunction

Alpha-blockers - mechanism of action

The sympathetic nervous system plays a significant role in regulating blood pressure. This control is mediated by adrenaline and norepinephrine stimulating adrenergic receptors located on the membranes of building cellsvarious organs. Their activation leads to the triggering of the body's reactions related to the state of fight or flight. One of the consequences of stimulating adrenergic receptors is an increase in blood pressure.

There are different types of adrenergic receptors that are found in specific tissues. There are alpha 1 adrenergic receptors in the smooth muscle of blood vessels. They are also found in the liver and lower urinary tract. The use of drugs blocking alpha1-adrenergic receptors leads to the relaxation of arteries and veins.

The effect of alpha-blockers on lipid metabolism is also therapeutically beneficial. The mechanism of this drug action has not been fully elucidated. It has been shown that drugs from this group inhibit the synthesis of cholesterol and its esters inside hepatocytes. In addition, it enhances the uptake of cholesterol from the blood through feedback.

Alpha blockers - division

Alpha-adrenergic receptor inhibitors are classified into two types:

Selective α1-blockers- these drugs selectively block the adrenergic receptors found in the muscles of the blood vessels. Thanks to this, they inhibit their contraction, with a limited influence on other parts of the body. Such substances include: prazosin, quinazoline derivatives, doxazosin, Terazosin, indoramin, urapidil.

Non-selective α1- and α2-blockers- these drugs interact with both alpha 1 adrenergic receptors, which are found in the muscles of blood vessels, as well as alpha 2. used in the treatment of hypertension, but their use was associated with an increase in the release of norepinephrine and adrenaline in the body, which resulted in tachycardia, sodium and water retention, and increased cardiac output.

Ultimately, this resulted in a reduction in antihypertensive efficacy with long-term therapy. Currently, non-selective alpha-blockers are used only in the treatment of phaeochromocytoma. Such drugs include phentolamine and phenoxybenzamine.

Alpha blockers can also be classified according to the length of time they work in the body after taking a dose. It is distinguished by:

  • short-acting alpha-blockers , e.g. prazosin
  • Long-acting alpha-blockers , e.g. doxazosin and Terazosin.

Alpha-blockers - advantages

  • well-known mechanism of operation
  • fast effectiveness
  • possibility of long-term therapy
  • beneficial effect on lipid metabolism - indicated in patients with atherosclerosis
  • beneficial in patients with mild hypertrophyprostate gland

Alpha-blockers and benign prostatic hyperplasia

Alpha-adrenergic receptor inhibitors are one of the drugs used in the treatment of benign prostatic hyperplasia. Substances belonging to this group block alpha receptors located in the bottom of the bladder, in the prostate parenchyma and in the prostate urethra.

Thanks to this, alpha-blockers improve the urethral flow and minimize the residual urine in the bladder. As a result, they soothe the symptoms associated with prostatic hyperplasia.

Alpha-blockers - side effects

Side effects that may occur after taking alpha-blockers:

  • orthostatic hypotension
  • fatigue
  • sleepiness
  • headaches
  • swelling of the nasal mucosa
  • fainting
  • weakness
  • puffiness
  • heart rhythm disturbance

A sharp drop in blood pressure may occur with the first dose of the drug administered by the patient. The consequence of this condition may be fainting and weakness. Therefore, it is advisable to take the medicine the first time in the evening before going to bed. The therapy begins with a small dose of the substance, which the doctor increases over time.

Alpha-blockers - contraindications for use

  • drug hypersensitivity
  • hypotension
  • orthostatic hypotension
  • breastfeeding period
  • pregnancy
About the authorSara Janowska, MA in pharmacyPhD student of interdisciplinary doctoral studies in the field of pharmaceutical and biomedical sciences at the Medical University of Lublin and the Institute of Biotechnology in Białystok. A graduate of pharmaceutical studies at the Medical University of Lublin with a specialization in Plant Medicine. She obtained a master's degree defending a thesis in the field of pharmaceutical botany on the antioxidant properties of extracts obtained from twenty species of mosses. Currently, in his research work, he deals with the synthesis of new anti-cancer substances and the study of their properties on cancer cell lines. For two years she worked as a master of pharmacy in an open pharmacy.

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