Impotence is the inability to attain or maintain an erection of the penis that is firm enough for sexual intercourse.


To initiate and maintain an erection, the penis must fill with blood. Nerve signals cause the blood to flow there. The blood vessels expand so blood can fill it. Meanwhile, other blood vessels constrict, trapping blood inside.

The following factors can cause erectile dysfunction:

Venous Leak

A leak in the blood vessels in the penis can allow blood to escape. This means that an erection cannot be made or may not last long. Injury or disease can cause a venous leak.

Neurovascular Function

  • Problems with nerve signals and blood flow
  • Nerve dysfunction—can reduce feeling in the penis, resulting in impotence
  • Diabetes]]> —interferes with nerve signals
  • Complete loss of nighttime erections
  • ]]>Hardening of the arteries]]> —can cause reduced blood flow
  • ]]>Peripheral neuropathy]]> , spinal cord injury, and surgery—can damage nerves
  • Side-effects from medications

Blood Vessels and Nerves of Male Pelvis

Nerves, blood vessels, penis
© 2009 Nucleus Medical Media, Inc.

Psychological Factors

The brain causes many of the nerve signals needed for an erection. Emotional problems may play a role in men who suddenly develop impotence.


Risk Factors

These factors increase your chance of developing impotence. Tell your doctor if you have any of these risk factors:



Symptoms include:

  • A less firm penis
  • Fewer erections


The doctor will ask about your symptoms and medical history, and perform a physical exam. Expect questions about the frequency, quality, and duration of your erections. Your answers may help the diagnosis.

The doctor will examine your penis, testes, and rectum. If a physical cause is suspected, you will need lab tests, including:

  • Hormone levels such as thyroid function tests
  • Prolactin levels
  • Testosterone levels

Nocturnal Penile Tumescence Testing

This test can help your doctor determine if the cause is due to emotional problems or physical problems.


Sometimes Doppler]]> imaging may be done to look at the blood flow. The test is also done to check for blockage in the arteries or veins that supply the penis.



Treatment options include:


Your doctor may prescribe:

  • Phosphodiesterase inhibitors, such as:
  • Oral ]]>testosterone]]> , if you have low testosterone levels
  • ]]>Alprostadil]]> , either injected into the penis or inserted into the urethra as a suppository

Use caution and talk to your doctor before taking any over-the-counter medicines for impotence. Some of them may be unsafe. ]]>]]>

Vacuum Devices

  • Plastic cylinder for the penis
  • Hand pump for pumping air out of the cylinder
  • Elastic band for holding the erection after removal of the cylinder

Vascular Surgery

Vascular surgery repairs venous leaks. This has been shown to be effective in some cases.

Penile Implants

There are semi-rigid, malleable, and inflatable implants. They are surgically inserted into the penis.

Penile Implant

penile implant smaller
© 2009 Nucleus Medical Media, Inc.

Sex Therapy

Sex therapy may help impotence resulting from:

  • Ineffective sexual techniques
  • Relationship problems
  • Anxiety
  • Depression



To reduce your chance of becoming impotent:

  • Take medications to manage blood pressure]]> , diabetes, or depression.
  • Ask your doctor about changing medications.
  • Maintain a ]]>healthy weight]]> .
  • Eat a ]]>healthful diet]]> .
  • If you smoke, ]]>quit]]> . Smoking is significantly associated with impotence in middle-aged and older men.
  • Talk to a ]]>therapist]]> or counselor.