Generic Viagra

I began a relationship nine months ago with a woman 11 years younger than me. I had a lot of emotional issues in my life at the time and, to my embarrassment, I found I had problems getting or maintaining an erection. I decided to try Viagra and it certainly solved my problem! My lady has been very kind and patient throughout this experience and I am happy to be able to give her complete sex rather than just oral. I have found that drinking a lot of water when I take the pill helps with the sinus stuffiness and facial flushing. There is a small loss of sensitivity that delays climaxing, but that turns out to be a good thing! - Bill, Age 58

If you want to create a drug that increases blood flow to the penis, there are at least three ways to do it:

1. Increase the amount of nitric oxide produced in the penis
2. Increase the amount of cGMP produced in the penis in response to the nitric oxide
3. Eliminate the PDE in the penis so that the cGMP builds up instead of getting decomposed by the PDE

Viagra uses method number three — it eliminates the PDE that is decomposing the cGMP, so cGMP builds up in the penis and has a larger effect on the artery walls. The greater the amount of cGMP the greater the blood flow, and the greater the blood flow the greater the degree of the erection.

The reason that Viagra uses this technique is because of an interesting quirk of PDE.

It turns out that the human body has at least 11 different kinds of PDE that it produces. Only one of those kinds of PDE — PDE5 — is found primarily in the penis. Once scientists discovered this fact, the creation of Viagra was relatively simple. All that Pfizer needed to find was a chemical that would selectively block PDE5 and nothing else. With the PDE5 blocked, cGMP could build up in the penis and increase the blood flow there without affecting other parts of the body.

If there were not a unique type of PDE found in the penis, we would not have Viagra today.

Aphrodisiac

Sildenafil is commonly and increasingly used as an aphrodisiac. While there is no clinical evidence that it has aphrodisiac activity, many seem to believe it will improve sexual performance as well as erectile function and enhance the sexual experience that will occur.

Recreational use

Viagra’s popularity with young adults has increased over the years. It is sometimes used recreationally. Some users mix Viagra with methylenedioxymethamphetamine (MDMA, ecstasy) in an attempt to compensate for the side effect common to many amphetamines of erectile dysfunction, a combination known as “sextasy”, “rockin’ and rollin’”, or ‘trail mix’.”

Prevention of plant wilting

A low-concentration solution of sildenafil in water significantly prolongs the time before cut flowers wilt; one experiment showed a doubling in time from one week to two weeks. The mechanism of action is similar to that in humans: nitric oxide leads to the production of cGMP whose degradation by PDE5 is inhibited by sildenafil.

Jet lag research

The 2007 Ig Nobel Prize in Aviation went to Patricia V. Agostino, Santiago A. Plano and Diego A. Golombek of Universidad Nacional de Quilmes, Argentina, for their discovery that Viagra aids jet lag recovery in hamsters. Their research was published in the Proceedings of the National Academy of Sciences.