Impotence (ED)

Erectile Dysfunction
(Impotence, ED)

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

• What is erectile dysfunction?
• How common is erectile dysfunction?
• What is normal penis anatomy?
• How does erection occur?
• How is erection sustained?
• What are the causes of erectile dysfunction?
• How is erectile dysfunction diagnosed?
• Patient history
• Physical examination
• Laboratory tests for erectile dysfunction
• Other tests for erectile dysfunction
• Psychosocial examination for erectile dysfunction
• What erectile dysfunction treatments are available?
• Adjusting medications
• Lifestyle improvements
• What medications are used to treat erectile dysfunction?
• sildenafil (Viagra)
• vardenafil (Levitra)
• tadalafil (Cialis)
• Intracavernosal injections
• Intraurethra suppositories
• Vacuum devices
• Surgery for erectile dysfunction
• What will the future bring for erectile dysfunction?
• Erectile Dysfunction At Glance
• Related erectile dysfunction articles:
  Erectile dysfunction - on WebMD
• Read what your doctor is reading:
  Erectile Dysfunction - on Medscape

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.