Viagra Science: How Viagra Works Physiology

When creating a drug that enhances blood flow to the penis, there are at least three methods to implement it:

1. Enhance the amount of nitric oxide (NO) produced in the penis
   
   
2. Enhance the amount of cyclic guanosine monophosphate (cGMP) developed in the penis in response to the NO
   
   
3. Eliminate the phosphodiesterase 5 (PDE) in the penis so the cGMP develops instead of being decomposed by the PDE

Viagra gets rid of the PDE so cGMP develop in the penis and has a greater impact on the artery walls. The greater the amount of cGMP, the greater the blood flow; the greater the blood flow the greater the strength of the erection. Viagra uses this routine because of an interesting quirk of PDE.

Unique PDE of Viagra

The human body produces at least 11 different types of PDE. Only one of those types of PDE (PDE5) is found in the penis. Once scientists noted this, the development of Viagra was relatively straightforward. Pfizer studied a chemical that would play a significant part in blocking PDE5 and nothing else. With the PDE5 blocked, cGMP could develop in the penis and enhance the blood flow there with no bearing on the other parts of the body. Were it not for this unique kind of PDE, there would be no Viagra.

Sildenafil citrate

PDE5 is an enzyme, a specially folded protein that plays a significant role in chemical reaction). PDE5 accepts cGMP and breaks it down. Pfizer needed a chemical that would not only hold PDE5 and keep it from doing its job. The chemical that Pfizer come up with is called sildenafil citrate. It fits right an outlet on the PDE5 enzyme and disables it.

Viagra consists of sildenafil citrate packaged as a pill. When a man takes a Viagra pill, the sildenafil citrate flows throughout his body, but has an impact only on the PDE5 enzyme in the penis. Viagra’s presence is felt in the bloodstream for about four hours, after which it is washed out of the blood by the liver and kidneys.

Expectations on effectiveness of viagra

In a research, more than 80% of men with ED had improved erections with the help of Viagra.  More importantly, Viagra can work irrespective of your age or the severity of your ED.