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December 15, 2009
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Erectile Dysfunction
(Impotence, ED)

Medical Author: Dennis Lee, MD
Medical Editors: Jay W. Marks, MD, and Jacob Rajfer, MD

Viagra: The Little Blue Pill That Could

Medical Author: Benjamin Wedro, MD, FAAEM
Medical Editor: Melissa Conrad Stöppler, MD

Learn how the use of Viagra has evolved.Once upon a time, there was a little blue pill. Its inventors were trying to treat heart disease and prevent heart attacks and found that the little blue pill could dilate blood vessels. The theory was that angina or chest pain could be decreased when more red blood cells carrying oxygen were delivered to heart muscle cells through the dilated coronary vessels. Though good in theory, since it works for nitroglycerin, clinically, the little blue pill wasn't very effective.

The little blue pill wasn't very specific as to where it dilated blood vessels. Not only were heart vessels dilated, but so were blood vessels in other places, and this side effect became its claim to fame. Viagra hit the market as the first treatment for erectile dysfunction and was a superstar.

It was also becoming a superstar in the athletic world. Studies with cyclists and mountain climbers found that at high altitude, the little blue pill dilated blood vessels in the lung and allowed more oxygen to be extracted from the air, increasing the oxygen concentration in the bloodstream. This translated into faster and stronger training. All of a sudden, the little blue pill moved from the bedroom to the playing field...please insert your own performance-enhancing joke here.

And so we have the latest revelation that baseball players are loading up on Viagra. No big surprise, since Viagra has been a hit on the pro cycling tour for a while, and baseball usually lags behind by a couple of years. History reminds us of anabolic steroids and growth hormone.

What is erectile dysfunction?

Erectile dysfunction (ED), also known as impotence, is the inability to achieve or sustain an erection for satisfactory sexual activity. Erectile dysfunction is different from other conditions that interfere with sexual intercourse, such as lack of sexual desire and problems with ejaculation and orgasm. This article focuses on the evaluation and treatment of erectile dysfunction.

How common is erectile dysfunction?

Erectile dysfunction (ED, impotence) varies in severity; some men have a total inability to achieve an erection, others have an inconsistent ability to achieve an erection, and still others can sustain only brief erections. The variations in severity of erectile dysfunction make estimating its frequency difficult. Many men also are reluctant to discuss erectile dysfunction with their doctors, and thus the condition is under-diagnosed. Nevertheless, experts have estimated that erectile dysfunction affects 30 million men in the Untied States.

While erectile dysfunction can occur at any age, it is uncommon among young men and more common in the elderly. By age 45, most men have experienced erectile dysfunction at least some of the time. According to the Massachusetts Male Aging Study, complete impotence increases from 5% among men 40 years of age to 15% among men 70 years and older. Population studies conducted in the Netherlands found that some degree of erectile dysfunction occurred in 20% of men between ages 50 to 54, and in 50% of men between ages 70 to 78. In 1999, the National Ambulatory Medical Care Survey counted 1,520,000 doctor-office visits for erectile dysfunction.

What is normal penis anatomy?

The penis contains two chambers, called the corpora cavernosa, which run the length of the upper side of the penis (see figure 1 below). The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa. Filling the corpora cavernosa is a spongy tissue consisting of smooth muscles, fibrous tissues, spaces, veins, and arteries. A membrane, called the tunica albuginea, surrounds the corpora cavernosa. Veins located in the tunica albuginea drain blood out of the penis.

Arteries and Veins Illustration - Erectile Dysfunction (ED)


Next: How does erection occur? »

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Erectile Dysfunction (Impotence)

Introduction

A sexual problem, or sexual dysfunction, refers to a problem during any phase of the sexual response cycle that prevents the individual or couple from experiencing satisfaction from the sexual activity. The sexual response cycle has four phases: excitement, plateau, orgasm, and resolution.

While research suggests that sexual dysfunction is common (43% of women and 31% of men report some degree of difficulty), it is a topic that many people are hesitant to discuss. Fortunately, most cases of sexual dysfunction are treatable, so it is important to share your concerns with your partner and doctor.

What causes sexual problems?

Sexual dysfunction can be a result of a physical or psychological problem.

  • Physical causes -- Many physical and/or medical conditions can cause problems with sexual function. These conditions include diabetes, heart and vascular (blood vessel) disease, neurological disorders, ho...

Read the Sexual (Sex) Problems in Men article »










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