Mechanism of action
Sildenafil citrate mechanism of action involves the release of nitric oxide (NO) in the corpus cavernosum of the penis. NO binds to the receptors of the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (cGMP), which muscle relaxation (vasodilatation) for smoothing the cushions of the intima of arteries helicinae, resulting increased blood flow and an erection.
Sildenafil is a potent and selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5) which is responsible for degradation of cGMP in the corpus cavernosum. The molecular structure of sildenafil is similar to that of cGMP and functions as a competitive binding agent of PDE5 in the corpus cavernosum, resulting in more cGMP and better erection. Without sexual stimulation, and therefore lack of activation of the NO / cGMP system, sildenafil should not cause an erection. Other drugs that, by the same mechanism tadalafil (Cialis) and vardenafil (Levitra) are operated.
Sildenafil is metabolised by liver enzymes and excreted by the liver and kidneys. Absorption When taken with a high fat meal reduced; time to maximum plasma concentration is increased by about an hour, and the maximum concentration itself is reduced to obtain about a third.
use:
1) Sexual dysfunction
The primary indication of sildenafil is treatment of erectile dysfunction (inability to fulfill to get a satisfactory erection traffic). It is now using the standard treatment for erectile dysfunction in all settings, including diabetes.
People on antidepressants may occur either sexual dysfunction because of their illness or as a result of their treatment. A 2003 study showed that sildenafil improved
sexual function in men in this situation. Up previous reports of 1999, found the same researchers found that sildenafil was able and sexual function in women, improve anti-depressants.
2) Pulmonary hypertension
In addition to erectile dysfunction, sildenafil citrate is also effective in the rare disease pulmonary arterial hypertension (PAH). It relaxes the artery wall, which reduces pulmonary arterial resistance and pressure. This reduces the workload of the right ventricle of the heart and improves symptoms of right heart failure. Because PDE-5 is primarily distributed within the arterial wall smooth muscle lung and penis, sildenafil acts selectively in both areas without vasodilation in other areas of the body to induce.
3) altitude
Sildenafil is for the prevention and treatment of pulmonary edema associated with altitude high altitude sickness, as they proved suffered by mountaineers to be useful. Although this effect was only recently discovered, sildenafil is already becoming an accepted treatment for this condition, especially in situations where delays the standard treatment of rapid descent for any reason.
4) Use in Sports
Professional sports players have been using drugs. It can open their blood vessels will enrich their muscles, increasing their effectiveness.
