Sildenafil citrate – treatment for erectile dysfunction. Restores the broken erectile function and provides natural response to sexual arousal.
Sildenafil is a potent and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5), which is responsible for the collapse of cGMP in the cavernous body. Sildenafil has no direct relaxing effect on the cavernous body but actively enhances the relaxing effect of nitric oxide in this tissue. During sexual arousal local release of NO under the influence of sildenafil leads to the inhibition of PDE5 and increased levels of cGMP in the cavernous body, this results in smooth muscle relaxation and increased blood flow in the cavernous body.
Sildenafil may cause mild and transient violation of distinguishing colors (blue/green). Alleged violations of the mechanism of color vision is the oppression PDE, which is involved in the transmission of light in the retina. In vitro studies have shown that the effect of sildenafil on PDE 10 times inferior to its activity against PDE5.
In vitro studies indicate that the activity of sildenafil against PDE5 in 10-10000 times higher activity against other isoforms of the phosphodiesterase (PDE 1, 2, 3, 4 and 6). In particular, the activity of sildenafil against PDE5 4000 times greater than its activity against PDE – camp-specific phosphodiesterase involved in the contraction of the heart.