Erexezil film-coated pills 100 mg N4
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Description
Erexezil pills - a drug for the treatment of erectile dysfunction. The active ingredient of the drug is sildenafil. A prerequisite for the effectiveness of sildenafil is sexual stimulation.
Active ingredients
Sildenafil
Release form
Pills
Pharmacological effect
Sildenafil is a potent selective cycloguanosine monophosphate (cGMP) inhibitor of type 5 phosphodiesterase (PDE5). The physiological mechanism of erection is associated with the release of nitric oxide (NO) in the cavernous body during sexual stimulation. This, in turn, leads to an increase in the level of cGMP, subsequent relaxation of the smooth muscle tissue of the cavernous body and an increase in blood flow. Sildenafil does not have a direct relaxing effect on the isolated cavernous body of a person, but enhances the effect of NO by inhibiting PDE5, which is responsible for the breakdown of cGMP. Sildenafil is selective for in vitro PDE5, its activity against PDE5 is superior to other known phosphodiesterase isoenzymes: PDE6 - 10 times, PDE1 - more than 80 times, PDE2, PDE4, PDE7 – PDE11 - more than 700 times. Sildenafil is 4,000 times more selective for PDE5 compared to PDE3, which is extremely important because PDE3 is one of the key enzymes regulating myocardial contractility. A prerequisite for the effectiveness of sildenafil is sexual stimulation.
Pharmacokinetics
Suction. After ingestion, sildenafil is rapidly absorbed from the gastrointestinal tract. Absolute bioavailability is 25-63%, an average of 40%. In vitro, sildenafil at a concentration of about 1.7 ng / ml (3.5 nM) inhibits human PDE5 activity by 50%. After a single dose of sildenafil in a dose of 100 mg, the average Cmax of free sildenafil in the blood plasma of men is about 18 ng / ml (38 nM). Cmax when taking sildenafil inside on an empty stomach is achieved on average within 60 minutes (from 30 to 120 minutes). When taken in combination with fatty foods, the absorption rate slows down, Cmax decreases on average by 29%, and the time it reaches (Tmax) increases by 60 minutes, however, the degree of absorption does not significantly change (AUC decreases by 11%). Distribution. The pharmacokinetics of sildenafil in the recommended dose range is linear. Vd of sildenafil in equilibrium is on average 105 l.Plasma protein binding of sildenafil and its main circulating N-demethyl metabolite is about 96% and does not depend on the total concentration of the drug. Less than 0.0002% of a dose of sildenafil (188 ng on average) was detected in semen 90 minutes after taking the drug. Metabolism. Sildenafil is metabolized mainly in the liver with the participation of CYP3A4 isoenzymes (main route) and CYP2C9 (secondary route). The main circulating active metabolite is formed as a result of N-demethylation of sildenafil and undergoes further metabolism. According to the selectivity of action against PDE, the metabolite is comparable to sildenafil, and the metabolite activity against PDE5 in vitro is about 50% of the activity of sildenafil. The concentration of metabolite in the blood plasma of healthy volunteers is approximately 40% of the concentration of sildenafil. The N-demethyl metabolite is further metabolized. Excretion. The total clearance of sildenafil is 41 l / h, and the final T1 / 2 is 3-5 h, the T1 / 2 of the N-demethyl metabolite is about 4 h. After ingestion, as well as after intravenous administration, sildenafil is excreted as metabolites mainly through the intestines (about 80% of the oral dose) and to a lesser extent by the kidneys (about 13% of the oral dose). Pharmacokinetics in special groups of patients. In healthy elderly patients (over 65), the clearance of sildenafil is reduced, and the concentration of free sildenafil in blood plasma is about 40% higher than in the young (18-45 years). Age does not have a clinically significant effect on the incidence of side effects. In case of renal failure, mild (CK 50-80 ml / min) and moderate (CK 30-49 ml / min) degree, the pharmacokinetics of sildenafil after a single dose of 50 mg do not change. With severe renal failure (CK <30 ml / min), the clearance of sildenafil decreases, resulting in an approximately twofold increase in the AUC value (100%) and Cmax (88%), compared with similar indicators in normal renal function in patients of the same age in patients with cirrhosis of the liver (Child-Pugh grades A and B), the clearance of sildenafil is reduced, which leads to an increase in the AUC value (84%) and Cmax (47%) compared with those in normal liver function in patients with same age group. The pharmacokinetics of sildenafil in patients with severely impaired liver function (Child-Pugh stage C) has not been studied.
Indications
Treatment of erectile dysfunction, characterized by the inability to achieve or maintain an erection of the penis, sufficient for satisfactory sexual intercourse.
Dosage and administration
The drug should be taken orally. The recommended dose for most adult patients is 50 mg approximately 1 hour before sexual activity. Given the efficacy and tolerability, the dose may be increased to 100 mg or reduced to 25 mg. The maximum recommended dose is 100 mg. The maximum recommended frequency of use is 1 time per day. Renal dysfunction With mild to moderate renal failure (CC 30–80 ml / min), dose adjustment is not required, with severe renal insufficiency (CC <30 ml / min), the dose of sildenafil should be reduced to 25 mg. Liver dysfunction As the excretion of sildenafil is impaired in patients with liver damage (in particular, in case of cirrhosis), the dose of sildenafil should be reduced to 25 mg. Combined use with other drugs When combined with ritonavir, the maximum single dose of sildenafil should not exceed 25 mg, and the frequency of use - 1 time in 48 hours (see the Interaction section). When combined with cytochrome CYP3A4 isoenzyme inhibitors (erythromycin, saquinavir, ketoconazole, itraconazole), the initial dose of the drug should be 25 mg (see the Interaction section). To minimize the risk of postural hypotension in patients taking? -Adrenoblockers, administration of Erexesil should be started only after stabilization of hemodynamics is achieved in these patients.