Tamsulosin is a specific blocker of postsynaptic * 1-adrenergic receptors, located in the smooth muscles of the prostate gland, the neck of the bladder and the prostatic part of the urethra. Blockade of * 1-adrenoreceptors with tamsulosin leads to a decrease in the tone of the smooth muscles of the prostate , Neck of the bladder and prostatic part of the urethra and improve the outflow of urine. Simultaneously, both emptying symptoms and filling symptoms are reduced, caused by increased tone of smooth muscles and detrusor hyperactivity in benign prostatic hyperplasia.
The ability of tamsulosin to act on the * 1A subtype of adrenoceptors is 20 times greater than its ability to interact with the * 1B subtype of adrenoreceptors, which are located in the smooth muscles of blood vessels. Due to its high selectivity, tamsulosin does not cause a clinically significant decrease in systemic blood pressure (BP) in both patients with arterial hypertension and in patients with normal initial BP.