Pharmacological action

Blocker of α1-adrenoreceptors; a remedy for the symptomatic treatment of benign prostatic hyperplasia.

Selectively blocks postsynaptic α1A-adrenergic receptors of smooth muscles of the prostate gland, bladder neck, prostatic urethra. As a result, the tone of the smooth muscles of these formations decreases, and the outflow of urine is facilitated. At the same time, the symptoms of obstruction and irritation associated with benign prostatic hyperplasia are reduced. The therapeutic effect appears approximately 2 weeks after the start of treatment.

The ability to block αmuch less pronounced in tamsulosin1B-adrenoreceptors of vascular smooth muscles is, therefore the effect on systemic blood pressure is insignificant.

Pharmacokinetics

After oral administration, tamsulosin is rapidly and almost completely absorbed from the gastrointestinal tract. After a single oral intake of 400 μg Cmax of the active substance in plasma is achieved after 6 hours.

Plasma protein binding is 99%. Vd is insignificant and amounts to 0.2 l / kg.

Tamsulosin is slowly metabolized in the liver to form pharmacologically active metabolites that retain high selectivity for α1A-adrenergic receptors. Most of the active substance is present in the blood unchanged.

T1/2 of tamsulosin with a single dose - 10 hours, terminal T1/2 is - 22 hours. It is excreted by the kidneys, 9% - unchanged.

Indications of the active substances of the drug Tamsulosin

Benign prostatic hyperplasia.

Dosing regimen

Inside - 400 mcg 1 time / day (after breakfast).

Contraindications to use

Hypersensitivity to tamsulosin.

Application for violations of liver function Use with

caution in patients with severe violations of liver function.

Application for impaired renal function

In patients with impaired renal function, changes in the dosage regimen are not required.

Special instructions

Use with caution in patients prone to arterial hypotension, with severe liver dysfunction.

Before starting tamsulosin therapy, the patient should be examined for other diseases that may cause the same symptoms as benign prostatic hyperplasia. Before starting treatment and regularly during therapy, a digital rectal examination and, if necessary, determination of a specific antigen of the prostate should be performed. In patients with impaired renal function, changes in the dosage regimen are not required.

Influence on the ability to drive vehicles and control mechanisms

During the period of treatment, it is necessary to refrain from engaging in potentially hazardous activities that require increased concentration of attention and speed of psychomotor reactions.

Drug interaction

With the simultaneous use of tamsulosin with cimetidine, there was a slight increase in the concentration of tamsulosin in the blood plasma, and with furosemide - a decrease in concentration; with other α1-adrenergic blockers - a pronounced increase in the hypotensive effect is possible.

Diclofenac and indirect anticoagulants slightly increase the rate of tamsulosin elimination.

Diazepam, propranolol, trichloromethiazide, chlormadinone, amitriptyline, diclofenac, glibenclamide, simvastatin and warfarin do not change the free fraction of tamsulosin in human plasma in vitro. In turn, tamsulosin also does not change the free fractions of diazepam, propranolol, trichloromethiazide and chlormadinone.

In studies in vitro, no interaction was found at the level of hepatic metabolism with amitriptyline, salbutamol, glibenclamide and finasteride.

Other α1-adrenergic blockers, acetylcholinesterase inhibitors, alprostadil, anesthetics, diuretics, levodopa, antidepressants, beta-blockers, slow calcium channel blockers, muscle relaxants, nitrates and ethanol can increase the severity of the hypotensive effect.

Side effect

From the side of the cardiovascular system: rarely - dizziness, orthostatic hypotension, palpitations.

From the side of the central nervous system: possible headache, asthenia.

From the reproductive system: rarely - retrograde ejaculation.