Millions of men worldwide suffer from male impotence or erectile dysfunction which is the inability to achieve or maintain an erection in order to participate in sexual intercourse. Many men older than 45 end up with erectile dysfunction, and sex drive is often even lower in older individuals who take various types of medications.

Many people assume that our sex drive will continue to decrease as we age which will inevitably lead to erectile dysfunction. However, most men who are unable to maintain an erection experience problems related to an actual physical condition, not reduced sexual desire.

Most individuals including trained urologists believed that erectile dysfunction as a psychological problem until the early 80s. However, during a presentation made by Dr. Giles Brindley in 1983 to the American Urological Association, he injected his own penis with the drug phentolamine to demonstrate that the drug could make it erect.

Brindley learned that by relaxing the blood vessels that led to the penis, more blood would flow to that are. This would cause the penis to inflate and become erect. Therefore, it became widely accepted that erectile dysfunction was actually caused by physical changes, rather than psychological or mental conditions in adult men.

How Viagra Controls The Penile Valve

The drug Dr. Brindley injected himself with, Phentolamine, was used in the 1980s and 90s. However, there were two problems with it: it can not target only the penis area so it can affect other body parts and the erections it causes are not associated with sexual stimulation. Therefore, you can experience an erection at any time while taking the drug which will continue until the drug ceases to take effect.

Viagra was created by the Pfizer company in 1998, and it was the first drug to address these two common problems. Viagra, which contains the active ingredient sildenafil citrate, enhances the processes that occur with sexual stimulation rather than relaxing the penis’ blood vessels. The drug controls the chemicals called “softeners” that are designed to make the penis go flaccid after an erection.

When men are sexually stimulated, their brain sends signals to trigger chemicals called “hardeners” that relax blood vessels in the penis. As the blood vessels relax, more hardeners are produced which increases blood flow and makes the penis erect.

While hardeners are relaxing the blood vessels, the body also produces softeners. These chemicals, an enzyme called phosphodiesterase (PDE5), help to neutralize and break down the hardeners which enables the erection to slowly subside.

If men produce more hardeners than softeners during sexual stimulation, they will be able to maintain an erection. However, once the level of hardeners being produced decreases, the softeners gain control and cause the erection to subside.

Erectile dysfunction is currently assumed to be caused by an imbalance of softeners and hardeners. The body produces excess softeners or too few hardeners; both conditions cause the inability to maintain or sustain an erection.

Viagra works by inhibiting the amount of softeners produced which increases the amount of hardeners present in the blood vessels of the penis. This helps men create a hard and long erection.

Fortunately, erections only occur when men who are taking Viagra are sexually stimulated. The drug allows the body’s natural chemicals to perform their required tasks. Once the brain stops creating hardeners after sex, the erection will gradually subside. The effects of Viagra also begin to subside within 4 to 5 hours of taking the drug.

Like any drug, Viagra can cause side effects. If you are taking any nitrate-based drug such as nitroglycerin or any heart or blood pressure medication, you should not take Viagra. The combination of drugs can cause a severe blood pressure drop. Individuals suffering from kidney or liver problems should also avoid taking Viagra.