Sildenafil Citrate is the active component of Fildena 25 .
PDE5 activation is inhibited by sildenafil.
Men's penile tissue naturally contains the enzyme PDE5.
The region becomes flaccid when the enzyme levels exceed average.
One way to do this is to restrict blood flow.
PDE5 levels are regulated by sildenafil.
It facilitates blood flow by aiding in blood artery dilatation.
A man can therefore achieve and maintain an erection.