Buy Sildenafil (Viagra) online.
Brand: OBLPHARM
Drug form: Tablets
Manufacturers: Russia
Active substance: Sildenafil
Group: Erectile Dysfunction Treatment, PDE-5 Inhibitor
Expiration date: 3 years
Important: this drug is a real sildenafil and the dosage corresponds to the claimed 100 mg. If you are taking Sildenafil for the first time, start with a dosage of 50 mg (take half the tablet or contact us, we have all the dosages including 25 mg).
Food and Drug Administration (FDA) has approved sildenafil citrate as the safest medicament for the treatment of male impotence. Moreover it is available at surprisingly low cost. Always confer with the doctor before using the drug.
Sildenafil (Viagra) tablets 100mg No. 10; 20
Indications for use of Sildenafil (Viagra) are:
Treatment of erectile dysfunction, characterized by an inability to achieve or maintain an erection of the penis sufficient to satisfy sexual intercourse. Effective only with sexual stimulation.
Pharmachologic effect:
Sildenafil is a potent selective inhibitor of cycloguanosine monophosphate (cGMP), a specific phosphodiesterase type 5 (PDE-5). Restores impaired erectile function in conditions of sexual stimulation of increased blood flow in the vessels of the penis. Mechanism of action The physiological process underlying penile erection involves the release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. Nitric oxide activates the enzyme guanylate cyclase, which leads to an increase in the concentration of cGMP and the subsequent relaxation of the smooth muscle cells of the corpus cavernosum and contributes to its filling with blood. Does not have a direct relaxing effect on the isolated corpus cavernosum, but enhances the effect of NO by inhibiting PDE-5, which is responsible for the breakdown of cGMP. When the NO / cGMP system is activated against the background of sexual stimulation, inhibition of PDE-5 under the action of sildenafil leads to an increase in the level of cGMP in the corpus cavernosum. For the development of the desired pharmacological action of sildenafil, sexual stimulation is imperative. In vitro studies have shown that sildenafil is selective for PDE-5, which is involved in the development of erection. Its activity against PDE-5 is superior to that against other known phosphodiesterases. Sildenafil is 10 times less selective for PDE-6, which takes part in photo transmission in the retina. At the maximum recommended doses, sildenafil is 80 times less selective for PDE-1 and 700 times or more for PDE-2, 3, 4, 7, 8, 9, 10, and 11. The activity of sildenafil for PDE-5 is approximately 4000 times higher than its activity against PDE-3 (cycloadenosine monophosphate (cAMP) - a specific phosphodiesterase) involved in the regulation of myocardial contractility. Sildenafil causes a slight and transient decrease in blood pressure, which in most cases has no clinical manifestations. The maximum decrease in systolic blood pressure in a horizontal position after taking sildenafil at a dose of 100 mg, on average, is 8.3 mm Hg. Art., and diastolic blood pressure - 5.3 mm Hg. Art. This decrease in blood pressure is due to the vasodilating effect of sildenafil, possibly associated with an increase in the concentration of cGMP in vascular smooth muscle cells. A single dose of sildenafil up to 100 mg is not accompanied by clinically significant ECG changes in healthy volunteers. Sildenafil has no effect on cardiac output and does not alter blood flow through stenotic arteries. In patients with erectile dysfunction and stable angina pectoris who regularly took antianginal drugs (except nitrates), the time to the onset of angina pectoris during an exercise test did not differ significantly after taking sildenafil compared with placebo. In some patients, 1 hour after taking 100 mg of sildenafil using the Farnsworth-Munsel 100 test, transient changes in the ability to distinguish shades of color (blue / green) were revealed; these changes were absent 2 hours after taking sildenafil. Inhibition of PDE-6 is considered to be the putative mechanism of color perception disturbance. Sildenafil has no effect on visual acuity or contrast perception, electroretinogram, intraocular pressure, or pupil diameter. It was noted that in patients with early age-related macular degeneration, sildenafil at a dose of 100 mg once did not cause clinically significant changes in vision, assessed by special tests (visual acuity, Amsler grating, traffic light color difference, Humphrey perimetry and photostress). A single dose of sildenafil 100 mg had no effect on sperm motility or morphology in healthy volunteers. Additional information on clinical trials In studies examining fixed doses of sildenafil, the proportion of men who reported improved erection was 62% (25 mg), 74% (50 mg) and 82% (100 mg), compared with 25% in the placebo group. At the same time, the frequency of sildenafil withdrawal was low and comparable to that in the placebo group. In all studies, the proportion of patients who noted an improvement in erection after using sildenafil was as follows: psychogenic erectile dysfunction (84%), mixed erectile dysfunction (77%), organic erectile dysfunction (68%), elderly patients (67%), diabetes mellitus (59%), ischemic heart disease (69%), arterial hypertension (68%), transurethral resection of the prostate (61%), radical prostatectomy (43%), spinal cord injury (83%), depression (75%). The analysis of the international index of erectile dysfunction showed that, in addition to improving erection, treatment with sildenafil also increased the quality of orgasm, made it possible to achieve satisfaction from intercourse and overall satisfaction. The safety and efficacy of sildenafil was maintained with long-term use.
Pharmacokinetics:
Suction Sildenafil is rapidly absorbed. Cmax in blood plasma when taken on an empty stomach is reached within 30-120 minutes (median 60 minutes). The absolute bioavailability, on average, is about 41% (25-63%). The pharmacokinetics (AUC and Cmax) of sildenafil in the recommended dose range (25-100 mg) is linear. Food intake reduces the absorption rate of sildenafil, and the time to reach Cmax is lengthened, on average, by 60 minutes, Cmax is reduced, on average, by 29%. Distribution The Vd of sildenafil in equilibrium is, on average, 105 liters. After a single oral dose of 100 mg of sildenafil, Cmax is approximately 440 ng / ml (coefficient of variation (CV) 40%). Since sildenafil (and its main circulating N-demethylated metabolite) is 96% bound to plasma proteins, the mean plasma concentration of the free fraction of sildenafil is 18 ng / ml (38 nM). In healthy volunteers, 90 minutes after a single dose of 100 mg of sildenafil, less than 0.0002% of the dose is determined in the semen (on average, 188 ng). Metabolism Sildenafil is metabolized mainly in the liver under the action of cytochrome P450 microsomal isoenzymes: CYP3A4 (main pathway) and CYP2C9 (additional pathway). The main circulating active metabolite is formed by N-demethylation of sildenafil. The selectivity of the metabolite to phosphodiesterases is comparable to that of sildenafil, and its activity against PDE-5 in vitro is approximately 50% of the activity of unchanged sildenafil. The concentration of the metabolite in the blood plasma of healthy volunteers is about 40% of the concentration of sildenafil. The N-demethylated metabolite undergoes further metabolism, its T1 / 2 is about 4 hours. Withdrawal The total clearance of sildenafil is 41 l / h, and the final T1 / 2 is 3-5 hours. Sildenafil is excreted as metabolites, mainly through the intestines (about 80% of the dose) and, to a lesser extent, by the kidneys (about 13% of the dose). Pharmacokinetics in patients of certain groups Elderly patients. In healthy elderly patients (65 years of age and older), the clearance of sildenafil is reduced, and the concentration of sildenafil and its active N-demethylated metabolite in blood plasma is approximately 90% higher than in young patients (18-45 years). Given the age-related characteristics of binding to blood plasma proteins, the concentration of free sildenafil in blood plasma increases by about 40%. Impaired renal function. In patients with mild or moderate renal impairment (CC 30-80 ml / min), the pharmacokinetics of sildenafil did not change after a single dose of 50 mg. The average AUC and Cmax of the N-demethylated metabolite increased by 126% and 73%, respectively, compared with healthy patients of the same age. Due to the high interindividual variability, these differences are statistically insignificant. In severe renal failure (CC less than 30 ml / min), the clearance of sildenafil decreases, which leads to an approximately two-fold increase in the AUC (100%) and Cmax (88%) values compared with those in patients of the same age group without functional impairment kidneys. Liver dysfunction. In patients with class A and B liver cirrhosis according to the Child-Pugh classification, the clearance of sildenafil decreases, which leads to an increase in AUC (84%) and Cmax (47%) compared with patients with normal liver function of the same age group. The pharmacokinetics of sildenafil in patients with severe hepatic impairment have not been studied.