Who can use Vidalista 20 mg?
Basic physical and chemical properties: tablets coated with a blue film shell, in the form of a diamond, with rounded edges, embossed with ” Pfizer “on the one hand and, accordingly, the dosage,” VGR 50 “or” VGR 100 ” – on the other.
Means used in erectile dysfunction. Cialis. ATC code G04B E03.
What do I need to know about Vidalista 20?
Mechanism of action. Sildenafil is a drug for oral administration, intended for the treatment of erectile dysfunction. With sexual arousal, the drug restores reduced erectile function by increasing blood flow to the penis.
The physiological mechanism that leads to erection Vidalista involves the release of nitric oxide (NO) in cavernous bodies during sexual arousal. The released nitric oxide activates the enzyme guanylate cyclase, which stimulates an increase in the level of cyclic guanosine monophosphate (cGMP), which in turn causes relaxation of the smooth muscles of the cavernous bodies, contributing to blood flow.
Sildenafil is a powerful and selective inhibitor of cGMP-specific phosphodiesterase 5 (FDE5) in cavernous bodies, where FDE5 is responsible for the breakdown of cGMP. The effect of sildenafil on erection is peripheral. Sildenafil does not have a direct relaxing effect on isolated cavernous human bodies, but powerfully enhances the relaxing effect of NO on this tissue. When you activate a metabolic pathway Tadalafil, what happens when sexual stimulation, inhibition sildenafilum ФДЕ5 leads to increased levels of cGMP in the cavernous bodies. Thus, in order for sildenafil to cause the necessary pharmacological effect, sexual arousal is necessary.
To use Vidalista 20
Influence on pharmacodynamics. In vitro studies have shown that sildenafil is selective for PDE5, which is actively involved in the erection process. The effect of sildenafil on FDE5 is more powerful than other known phosphodiesterases. This effect is 10 times more powerful than the effect on PDE6, involved in the processes of photopreformation in the retina. When using maximum recommended doses for sildenafil PDE5 selectivity to 80 times greater than its selectivity for ФДЭ1, 700 times higher than Vidalista. In particular, the selectivity of sildenafil to PDE5 is 4000 times higher than its selectivity to pdez – camp-specific isoform of phosphodiesterase involved in the regulation of cardiac contractility.
Possible side effects Vidalista 20
Absorption. Sildenafil is rapidly absorbed. The maximum Cialis concentration of the drug is achieved within 30-120 minutes (with a median of 60 minutes) after its oral application on an empty stomach. The average absolute bioavailability after oral administration is 41 % (with a range of values from 25 to 63 %). In the recommended dose range (from 25 to 100 mg), the indicators of AUC and Cmax of sildenafil after oral administration are increased proportionally to the dose.
In the application of sildenafil during meals extent of absorption is reduced, with an average elongation Tmax of 60 min and an average decrease in Cmax of 29 %.
Vidalista 20 from India Side Effects:
Distribution. The average equilibrium volume of distribution (Vd) is 105 liters, which indicates the distribution of the drug in the tissues of the body. After a single oral administration of sildenafil at a dose of 100 mg, the average maximum total plasma concentration of sildenafil is approximately 440 ng / ml (coefficient of variation is 40 %). Since the binding of sildenafil and its main N-desmethyl metabolite to plasma proteins reaches 96 %, the average maximum plasma concentration of free sildenafil reaches 18 ng/ml (38 nmol). The degree of binding to plasma proteins does not depend on the total concentrations of sildenafil.
What is in Vidalista 20?
In healthy volunteers who used sildenafil once in a dose of 100 mg, after 90 minutes less than 0.0002 % (average 188 ng) of the applied dose was determined in the ejaculate.
Biotransformation. The metabolism of sildenafil is carried out mainly with the participation of microsomal liver isoenzymes CYP3A4 (main pathway) and CYP2C9 (secondary pathway). The main circulating metabolite is formed by N-demethylation of sildenafil. The selectivity of the metabolite relative to ФДЕ5 comparable with sildenafil selectivity and activity of the metabolite relative to Vidalista is approximately 50 % activity of the initial substance. The plasma concentration of this metabolite is approximately 40% of the concentration of sildenafil in plasma. The n-demethylated metabolite is further metabolized and its half-life is approximately 4 hours.
Elimination. The total clearance of sildenafil is 41 l/h, causing a half-life of 3-5 hours. Both after oral and after intravenous administration, the excretion of sildenafil in the form of metabolites is carried out mainly with feces (about 80% of the administered oral dose) and to a lesser extent with urine (about 13% of the administered oral dose).
Who can use Vidalista 20?
Elderly patients. In healthy elderly volunteers (over 65 years), there was a decrease in the clearance of sildenafil, which led to an increase in plasma concentrations of sildenafil and its active n-demethylated metabolite by about 90% compared with the corresponding concentrations in healthy younger volunteers (18-45 years). Due to age differences in plasma protein binding, the corresponding increase in the plasma concentration of free sildenafil was approximately 40 %.
Renal failure. In volunteers with impaired renal function mild to moderate (creatinine clearance 30-80 ml / min) pharmacokinetics of sildenafil remained unchanged after a single oral administration at a dose of 50 mg.Average AUC and Cmax N-demethylated metabolite increased by a maximum of 126% and a maximum of 73%, respectively, compared with such indicators in volunteers of the same age without impaired renal function. However, due to high individual variability, these differences were not statistically significant. In volunteers with severe renal impairment (creatinine clearance below 30 ml / min), sildenafil clearance decreased, leading to average increases in AUC and Cmax by 100% and 88%, respectively, compared with volunteers of the same age without renal impairment. In addition, the values of AUC and Cmax of N-demethylated metabolite significantly increased by 200% and 79%, respectively.
Where can I buy Vidalista 20?
Liver failure. In volunteers with mild to moderate cirrhosis of the liver (classes A and B according to the classification of child – Pugh) clearance of sildenafil decreased, which led to an increase in AUC (84 %) and Cmax (47 %) compared with the corresponding indicators in volunteers of the same age without liver dysfunction. The pharmacokinetics of sildenafil in patients with severe liver dysfunction has not been studied.
The drug Viagra® is recommended for men with erectile dysfunction, which is defined as the inability to achieve or maintain erection of the penis, necessary for successful sexual intercourse.
For the effective action of the drug Viagra® requires sexual arousal.
Hypersensitivity to the active substance or any of the excipients of the drug.
Coadministration with nitric oxide donors (such as amyl nitrite) or nitrates in any form is contraindicated because it is known that sildenafil affects the pathways of nitric oxide/cyclic guanosine monophosphate (cGMP) metabolism and potentiates the hypotensive effect of nitrates.
Concomitant use of PDE5 inhibitors (including sildenafil) called guanylate cyclase stimulants such as riociguat, is contraindicated because it may lead to symptomatic hypotension (see section “interaction with other medicinal products and other forms of interaction”).
Conditions in which sexual activity is not recommended (e.g. severe cardiovascular disorders such as unstable angina or severe heart failure).
Loss of vision in one eye due to non-arterial anterior ischemic optic neuropathy, regardless of whether this pathology is related to the previous USE of PDE5 inhibitors or not.
The presence of diseases such as severe liver dysfunction, hypotension (blood pressure below 90/50 mm Hg. St.), recent stroke or myocardial infarction, and known hereditary degenerative retinal diseases such as pigment retinitis (a small number of such patients have genetic disorders of retinal phosphodiesterases), since the safety of sildenafil has been investigated in such subgroups of patients.
Do you recommend Vidalista 20 use?
Interaction with other drugs and other types of interactions
The effect of other drugs on sildenafil.
In vitro studies. Metabolism of sildenafil occurs mainly with the participation of isoforms ZA4 (major route) and 2C9 isoforms (minor route) cytochrome P450 (CYP). Therefore, inhibitors of these isoenzymes may reduce sildenafil clearance and inducers of these isoenzymes may increase sildenafil clearance.
Vidalista 20 mg Manufacturer
Research in vivo. Population pharmacokinetic analysis of clinical trial data have demonstrated a reduced clearance of sildenafil with simultaneous use with inhibitors of CYP3A4 (such as ketoconazole, erythromycin, cimetidine). Although the simultaneous use of sildenafil and CYP3A4 inhibitors increase in the frequency of side effects was not observed, it should be considered the possibility of using an initial dose of sildenafil 25 mg.