Tamsulosin

Pharmacological properties

adenorm selectively and competitively blocks postsynaptic α1-adrenergic receptors, in particular α1a and α1d, located in the smooth muscles of the prostate gland, bladder neck and prostatic urethra. this leads to a decrease in the tone of the smooth muscles of the prostate gland, neck of the bladder and the prostatic part of the urethra and an improvement in the outflow of urine. at the same time, the severity of symptoms of obstruction and irritation associated with benign prostatic hyperplasia (difficulty in starting urination, weakening of the urine stream, dripping after urination is completed, feeling of incomplete emptying of the bladder, frequent urination at night, urination at night).

These effects persist for a long time with long-term treatment and significantly delay the conduct of surgery or catheterization.

Antagonists α₁-adrenoreceptors have the ability to lower blood pressure by lowering the peripheral vascular tone. When conducting tests of the drug Adenorm, no clinically pronounced decrease in blood pressure was noted.

Pharmacokinetics

Suction. Tamsulosin is well absorbed in the digestive tract, and its bioavailability is almost 100%. The absorption of tamsulosin is somewhat slower after eating. Uniformity of absorption is achieved when the patient takes Adenorm at the same time after eating. The pharmacokinetics of tamsulosin is linear.

When taking a single dose of the drug after eating, the peak concentration of tamsulosin in the blood plasma is reached after about 6 hours, and a stable concentration is formed on the 5th day after daily administration of the drug. C_max approximately ⅔ higher than that achieved after taking a single dose.

Distribution. In men, tamsulosin is approximately 99% bound to plasma proteins. The volume of distribution of the drug is insignificant (about 0.2 l / kg).

Metabolism. Tamsulosin hydrochloride is not susceptible to the first-pass effect and is slowly metabolized in the liver with the formation of pharmacologically active metabolites that retain high selectivity for α₁-adrenoreceptors. Most of the active substance is present in the blood unchanged.

Elimination. Tamsulosin and its metabolites are excreted primarily in the urine. About 9% of the dose remains as unchanged active substance.

After a single dose after a meal and at a stable plasma concentration T_½ is about 10 and 13 hours, respectively.

Indications

Treatment of functional disorders of the lower urinary tract with benign prostatic hyperplasia.

Application

The recommended dose for adults is 1 capsule daily after breakfast; the capsule should be swallowed whole with milk or water (about 150 ml), standing or sitting; take the whole capsule without chewing, as this will interfere with the modified release of the active ingredient.

Contraindications

Hypersensitivity to tamsulosin hydrochloride, including drug-induced angioedema, or any of the excipients; history of orthostatic hypotension; severe liver failure.

Side effects

From the nervous system: dizziness; headache; fainting.

From the side of the organ of vision: blurred vision, visual impairment.

On the part of the cardiovascular system: palpitations; orthostatic hypotension.

Respiratory mediastinal disorders: rhinitis; nose bleed.

From the gastrointestinal tract: constipation, diarrhea, nausea, vomiting.

On the part of the skin and mucous membranes: rash, itching, urticaria; angioedema; Stevens-Johnson syndrome; erythema multiforme, exfoliative dermatitis.

From the reproductive system: ejaculation disorders, including retrograde ejaculation and ejaculation failure.

General disorders: asthenia.

Cases of intraoperative instability of the iris of the eye (narrowed pupil syndrome) during cataract and glaucoma surgery in patients who took tamsulosin (see SPECIAL INSTRUCTIONS) are described.

In addition to the above adverse reactions, cases of atrial fibrillation, arrhythmias, tachycardia and dyspnea have been reported, the incidence of which cannot be reliably established.

special instructions

As with other blockers of α1-adrenergic receptors, in some cases, when using the drug adenorm, a decrease in hell is possible, which can sometimes lead to loss of consciousness. when the first signs of orthostatic hypotension appear (dizziness, weakness), the patient should crouch or take a horizontal position until the above symptoms disappear.

Before starting treatment with Adenorm, you should undergo a medical examination to identify other concomitant diseases that can cause the same symptoms as benign prostatic hyperplasia. Before starting treatment, it is necessary to conduct a rectal examination of the prostate gland and, if necessary, a test to determine the level of specific antigen of the prostate gland (PSA) before and after the same periods during treatment.

Prescribing the drug to patients with severe renal failure (creatinine clearance of 10 ml / min) is necessary with extreme caution, since clinical studies on the use of the drug in these patients have not been conducted.

In some patients who used tamsulosin, atonic pupil syndrome (IFIS, a variant of the narrowed pupil syndrome) was observed during cataract and glaucoma surgery, which can cause an increase in the number of complications during or after such an operation.

As a rule, it is recommended to discontinue treatment with tamsulosin 1–2 weeks before surgery for cataracts and glaucoma, but the benefits of discontinuing treatment with tamsulosin have not been clearly established today. Atonic pupil syndrome has also been reported in patients who discontinued tamsulosin long before surgery for cataracts.

Patients before a planned operation for cataracts or glaucoma are not recommended to start the use of tamsulosin hydrochloride. In preparation for surgery, surgeons and ophthalmologists should find out if the patient has used (or is using) tamsulosin in order to prevent possible complications associated with IFIS.

Tamsulosin hydrochloride should not be prescribed in combination with potent CYP 3A4 inhibitors in patients with low CYP 2D6 metabolism.

Tamsulosin hydrochloride should be used with caution in combination with potent and moderate CYP 3A4 inhibitors (see INTERACTIONS).

The drug contains sugar, which should be considered in patients with diabetes.

There are known cases of allergic reactions to tamsulosin in patients with a history of sulfanilamide allergies. Caution should be exercised when using tamsulosin hydrochloride in patients who have previously been allergic to sulfonamides.

Use during pregnancy and lactation. Adenorm is not indicated for use in women.

Fertility. Available data indicate that during the use of tamsulosin there were cases of impaired ejaculation, retrograde ejaculation and insufficient ejaculation.

Children. Do not use the drug in children. The safety and effectiveness of tamsulosin in children (under the age of 18 years) were not evaluated.

Influence on the ability to drive vehicles and work with complex mechanisms. Studies of the effect of the drug on the ability to drive vehicles or mechanisms have not been conducted. However, patients should be warned about the possibility of dizziness.

Interactions

Interaction studies were conducted only in adults.

With the simultaneous use of tamsulosin with atenolol, enalapril, nifedipine or theophylline, drug interactions were not observed. The simultaneous use with cimetidine increases, and with furosemide, it reduces the concentration of tamsulosin in the blood plasma, but since these levels remain within normal limits, there is no need for special dose adjustment of tamsulosin.

It is known that diazepam, propranolol, trichloromethiazide, chlormadinone, amitriptyline, diclofenac, glibenclamide, simvastatin and warfarin do not affect the free fraction of tamsulosin in human plasma. Similarly, tamsulosin does not change the level of free fractions of diazepam, propranolol, trichloromethiazide and chlormadinone in human blood plasma.

However, diclofenac and warfarin may increase the rate of elimination of tamsulosin.

The simultaneous use of tamsulosin hydrochloride with potent inhibitors of CYP 3A4 can lead to an increase in the effect of tamsulosin hydrochloride. Concomitant use with ketoconazole (a known potent inhibitor of CYP 3A4) led to an increase in AUC and C_max up to 2.8 and 2.2, respectively.

Tamsulosin hydrochloride should not be prescribed in combination with potent CYP 3A4 inhibitors in patients with low CYP 2D6 metabolism.

Tamsulosin hydrochloride should be used with caution in combination with potent and moderate CYP 3A4 inhibitors.

The simultaneous use of tamsulosin hydrochloride and paroxetine (a powerful inhibitor of CYP 2D6) leads to an increase in C_max and AUC to 1.3 and 1.6, respectively, but this is not clinically significant.

Concomitant use with other α blockers₁β-adrenoreceptors may enhance the hypotensive effect.

Overdose

Symptoms an overdose of tamsulosin hydrochloride can cause severe hypotensive effect. severe hypotensive effect was observed with varying degrees of overdose.

Treatment. In the case of a sharp decrease in pressure due to an overdose, maintenance therapy should be carried out aimed at restoring the normal function of the cardiovascular system (for example, the patient should take a horizontal position). If this measure does not work, carry out infusion therapy and prescribe vasopressor drugs. It is necessary to monitor renal function and conduct general supportive therapy. Due to the high degree of binding of tamsulosin to plasma proteins, hemodialysis is unlikely to be appropriate.

In order to stop further absorption of the drug, vomiting can be artificially induced. In case of an overdose of a significant amount of the drug, the patient must rinse the stomach with activated charcoal and low osmosis laxatives, such as sodium sulfate.

Storage conditions

In the original packaging at a temperature not exceeding 25 ° C.