Erectile Dysfunction

Erectile dysfunction (impotence) is difficulty achieving or maintaining an erection.

Occasionally, every man has difficulty achieving an erection. Erectile dysfunction occurs when the problem is frequent or continuous. Erectile dysfunction becomes more common with aging. Although about half of men aged 65 or over and three fourths of men aged 80 or over have erectile dysfunction, it is not a normal part of aging.

For erections to occur during sexual activity, there must first be interest in sexual activity. Such interest requires enough testosterone as well as stimulation by sexual thoughts, sights, smells, or touch. Men also need enough energy to participate. Blood must be able to get to the penis (through arteries). Muscles at the base of the penis must contract, squeezing (compressing) the veins there and thus preventing blood from leaving the penis. Blood then fills the fibrous tissue in the penis (corpora cavernosa), causing the penis to become larger (called engorgement). As a result, the penis becomes rigid. Involuntary (autonomic) nerves control the process. Aging itself does not prevent the process from working.

Causes

Erectile dysfunction may be caused by mental or emotional factors or by physical disorders. It can also result from taking certain prescription or nonprescription drugs or drinking too much alcohol.

For additional detail on this topic, see Causes of Erectile Dysfunction.

Symptoms and Diagnosis

Some men with erectile dysfunction have a decreased sex drive (libido), particularly if the testosterone level is low. However, many men with erectile dysfunction have a normal sex drive. Regardless of sex drive, men with erectile dysfunction have difficulty engaging in sexual intercourse. Either the erect penis is not hard enough for penetration or the erection cannot be maintained. Men with severe erectile dysfunction may not be able to achieve an erection.

To diagnose erectile dysfunction, a doctor examines the man's genitals and rectum. During the examination, the doctor evaluates how the nerves and blood vessels that supply the genitals are functioning. The pulse and blood pressure in the legs are measured. Abnormalities in these measurements may indicate a problem with arteries in the pelvis and groin that supply blood to the penis. If a problem with the arteries or veins is suspected, ultrasonography is done to check for blockages in the arteries of the penis. A blood sample is often taken to measure the testosterone level.

Treatment

Depending on the cause, the only treatment needed may be reducing alcohol consumption, having a doctor substitute a different drug, or taking testosterone therapy. Psychologic therapy that deals with the mental and emotional factors contributing to erectile dysfunction sometimes corrects the dysfunction. In contrast, if the blood vessels or nerves supplying the penis are damaged, dysfunction usually cannot be fully corrected. However, with treatment, an erection may be possible despite the damage.

Most drugs used to treat erectile dysfunction work regardless of the cause. However, these drugs are particularly effective if erectile dysfunction results from inadequate blood flow to the penis. Most of them increase blood flow to the penis. Examples are sildenafil, tadalafil, and vardenafil. These drugs are taken by mouth. Men who take a nitrate, such as nitroglycerin, to treat a heart disorder should not take sildenafil, tadalafil, or vardenafil. If nitrates are taken within several hours of taking one of these drugs, blood pressure may become dangerously low, and occasionally, death results. Alprostadil also increases blood flow to the penis. This drug is inserted into the urethra as a pellet (suppository). Some drugs (such as alprostadil given alone or with papaverine and phentolamine) can be injected into the penis if sildenafil, tadalafil, or vardenafil does not help.

Mechanical devices can increase the amount of blood in the penis and thus help men achieve erections. For example, constriction devices, such as bands and rings made of rubber or leather, can be placed at the base of the penis to slow the flow of blood out of the penis. Constriction devices can be purchased with a doctor's prescription in a pharmacy. Inexpensive versions (often called "cock rings") can be purchased in stores that sell sexual paraphernalia.

Constriction devices should not be left on for more than 30 minutes. Occasionally, they cause bruising, particularly in men who have a blood clotting disorder or who are taking a drug that makes blood less likely to clot (anticoagulant).

Constriction devices are often used with an alprostadil suppository or a vacuum device.

A vacuum device consists of a hollow chamber attached to a source of suction. The device fits over the penis, creating a seal. When suction is applied, blood is drawn into the blood vessels in the penis. After an erection is achieved, a constriction device is used to keep blood in the penis, maintaining the erection.

When all other treatments are ineffective, a prosthesis can be surgically implanted in the penis. Several types of prostheses are available. For example, firm rods may be inserted into the penis. This prosthesis makes the penis permanently hard. Or an inflatable balloon may be inserted into the penis. Before having intercourse, the man inflates the balloon with a small pump, which may be part of the prosthesis.

See the sidebar Mental and Emotional Causes of Sexual Dysfunction.

See the sidebar Testosterone Therapy: Treatment for Male Menopause?