Viagra

Viagra actually had a very conventional birth. Sildenafil Citrate was initially developed in Pfizer's research laboratory to treat patients who had problems with their blood pressure or heart disease. During the initial clinical studies, men taking the drug discovered an unexpected -Side Effect - that the drug could improve and maintain their erection.

Realizing the market potential of such a formulation, Pfizer immediately started clinical trials in healthy volunteers. These clearly established the action of Viagra. When Viagra was tried in patients with erectile dysfunction, the effects were astounding. By 1997, there were already 10 published studies from indexed journals. Soon in 1998, there were over 120 publications and by 1999, 200 reports. Viagra showed astounding prowess in erectile dysfunction treatment, more than 80% people suffering from impotence got a successful erection after taking Viagra.

Patented in 1996 by manufacturer Pfizer, Viagra got the FDA's approval for the treatment of erectile dysfunction on March 27, 1998. No other drug was approved before in the US to treat Erectile Dysfunction. Viagra was a huge hit soon after its launch. The reasons for the massive popularity of these diamond shaped blue pills were quite simple and obvious. Millions and millions of men all over the world suffer from suffer form of erectile dysfunction, which has distressed their sexual lives.

The causes for such impotence may be psychological, resulting from stress, fatigue, anxiety, or depression. But over 90% of the time, there are identifiable biological problems. The ED or impotence is prominent amongst men over 50 due to various hormonal changes in the body. This could result in partial or total loss of sexual function. It is here that Viagra scores over the traditional treatment options like penile implants, injectable drugs (into the penis), and vacuum constriction devices.

Viagra promotes erections by relaxing the smooth muscle of the blood vessels thus increasing blood flow in the penis in response to sexual stimulation. It does this by specifically blocking a particular enzyme (protein that assists chemical reactions) called phosphodiesterase type 5 (PDE 5). This is the enzyme that normally breaks down chemicals causing the erectile response. Therefore, by blocking the breakdown of erectile chemicals, the drug promotes a harder and more prolonged erection.

Viagra promotes penile erection only in response to sexual stimulation and has no effect in the absence of sexual stimulation. Therefore, if a healthy man took Viagra and occupied himself with usual daily activities, he would not be expected to develop an erection within the five or six hours in which the drug is active unless sexual stimulation took place.

Viagra improves erections in men with erectile dysfunction regardless of the cause. Specifically, it can improve erections in 70 per cent of patients treated for hypertension and in 57 per cent of patients with diabetes.