Viagra (Sildenafil Citrate)
What Is Viagra
Viagra is a brand name the Pfizer company gave to a chemical called sildenafil citrate. It is used as a medication to treat erectile dysfunction (also called impotence). Erectile dysfunction is the inability to have or maintain an erect penis for satisfactory sexual performance.
In the late 1980's and 1990's, the Pfizer company was doing research with a chemical known as UK-92480. It was being investigated as a treatment for angina and high blood pressure. During clinical trials it was noticed that the drug did not help angina and high blood pressure sufferers as much as was hoped.
However, some of the men who were taking part in the tests reported that after consuming sildenafil citrate, they got an erection when their penis was stimulated by touch.
Even more important was the fact that men who had previously been diagnosed as impotent were getting the same results as men who had no history of erectile dysfunction.
Pfizer decided to test sildenafil citrate for treating impotence with some very impressive results. Viagra was then patented in 1996, and in 1998 it was approved by the F.D.A. as the first oral medication to treat erectile dysfunction.
How Does Viagra Work
Medications like viagra, cialis, and levitra work by inhibiting a chemical called phosphodiesterase type 5. Because of their mode of action, these drugs are commonly referred to simply as PDE5 inhibitors.
When a man gets sexually excited, it triggers cells in the penis to produce nitric oxide. The increase in nitric oxide will in turn cause production of cyclic guanosine monophosphate (cGMP). The cGMP causes arteries in part of the penis to relax and allow more blood to flow through them. The increase in blood flow causes an erection.
If the enzyme phosphodiesterase type 5 (PDE5) is of sufficient quantity, it will attack the cGMP and erection will not be maintained. Viagra and other PDE5 inhibitors reduce the amount of PDE5 available to attack cGMP. With a reduction of PDE5, most men are able to maintain an erection to orgasm.
Does Viagra Work For Every Man Men with psychological impotence (erectile dysfunction caused by mental factors like stress) respond very well to viagra, cialis, and levitra as long as there are no underlying physical reasons that are causing problems.
There are various physical reasons for erectile dysfunction, but one of the most common reasons (especially in men over forty years of age) is that arteries in part of the penis are not relaxing enough to allow more blood to flow through them.
Even when sexually aroused, the amount of PDE5 is too large. The quantity of cGMP produced is overwhelmed, and an erection can not be developed or maintained for any period of time.
When a man takes viagra, in about 30 minutes, enough PDE5 inhibitor will be available to the penis to cause an erection when the penis is stimulated by touch.
Viagra will not work for every man with erectile dysfunction, but medical tests and reports from actual viagra consumers report that it works for about 60%-80% of the men who try it.
Before considering taking viagra for the first time, there are certain things a person should be aware of when deciding if it is right for them. See the viagra faq for some of the most frequently asked questions about viagra. Besides basic information, it includes viagra side effects and interactions with other drugs.
If you think viagra is right for you, you can compare prices, get a prescription written by a doctor, and have an order of viagra filled and sent to you online.
The only product the works exactly the same as viagra is generic viagra. Beware of products sold with viagra in their name, to make them appear to be similar to, or affiliated with, real viagra. Things like herbal viagra, natural viagra, and other similar substances do not work and should be avoided.
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