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rectile dysfunction (impotence), in which the penis cannot become erect or sustain an erection, was until recently not often talked about. Then in the spring of 1998, along came Viagra® (sildenafil), a drug that enables about half of all men who take it to produce and maintain erections. The drug was originally developed to treat chest pain. Its effects on the penis were noted when participants in the clinical trials reported improved sex lives, and refused to return extra pills! In most cases, Viagra appears to be safe and effective for men.

Jokes ran rampant, at first, until people began to realize how helpful the drug can be. One prominent ad featured an ex-vice president describing his problem, and another interviewed a very wide variety of satisfied customers, sending the message that erectile dysfunction is both common and not a laughing matter.

Erectile dysfunction has many causes, including underlying diseases such as diabetes mellitus; paralysis; treatments such as prostate surgery and many types of drugs, such as certain anti-depressants; and lifestyle factors such as excess smoking or drinking alcohol. Side effects of Viagra include headache, facial flushing, and gastrointestinal upset. Men taking nitrate drugs to treat angina should not take Viagra, because the combination can cause life-threatening drops in blood pressure.

Viagra is based on sound science. The process of erection depends upon a very small molecule, nitric oxide (NO), that until recently was most widely known as a constituent of smog, cigarette smoke, and acid rain.

The penis consists of two chambers of spongy tissue that surround blood vessels. When the vessels fill with blood, as they do following sexual stimulation, the organ engorges and stiffens. The stimulation causes neurons as well as the endothelial cells that line the interiors of the blood vessels to release NO. The NO then enters muscle cells that form the middle layers of the blood vessels, relaxing them by activating a series of other chemicals. The vessels dilate and fill with blood, and the penis becomes erect. One such chemical, cGMP, must stay around for awhile for an erection to persist. Viagra works by blocking the enzyme that normally breaks down cGMP, thereby sustaining the erection.

Viagra is only one of several new treatments for erectile dysfunction. Evaluating them is challenging, because of a powerful placebo effect. Other therapies are being developed and tested in rats by measuring pressure in the penis. In more people-oriented investigations, participants keep diaries that record "daily erectile activity" while taking a new drug versus taking a placebo, or are asked to answer detailed questions about their sex lives. Some studies use more invasive techniques. In "penile plethysmography," a volunteer watches an erotic film after taking a drug or placebo, while a device measures engorgement at the base of the penis. In an "audiovisual stimulation penogram," the penis is attached to a mercury-based strain gauge, which assesses engorgement as the man watches a movie.

Naturally Cure Erectile Dysfunction

Naturally Cure Erectile Dysfunction

Whether we like it or not, for many men it gets increasingly difficult to perform sexually as the years advance.

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