Erectile dysfunction, sometimes called "impotence," is the repeated inability to get or keep an erection firm enough for sexual intercourse.

Erectile dysfunction, or ED, can be a total inability to achieve erection, an inconsistent ability to do so, or a tendency to sustain only brief erections. These variations make defining ED and estimating its incidence difficult.

Erectile Dysfunction Statistics:

• One in 10 men in the world have erectile dysfunction.
• 30 million men in the United States have erectile dysfunction.
• 50% of men with diabetes have erectile dysfunction, frequently within 10 years of diagnosis.
• The likelihood of erectile dysfunction increases with age: 39% at age 40, 65% over the age of 65.
• Smokers have a higher likelihood of erectile dysfunction. Men who smoke more than 1 pack per day have a 50% higher chance of impotency than nonsmokers the same age.

Erectile Dysfunction Appears to be on the Rise (no pun intended):

• More men are experiencing impotency because the baby boomer generation is getting older. According to same reports, every 7 seconds a baby boomer turns 50 years old.
• Awareness of the problem is increasing, which increases the number of men who are treated.
• Because, in the past, men have generally been unwilling to talk about their problem or seek treatment, erectile dysfunction has been underreported.
• Many physicians are not aware of the treatment options, so patients have been either under treated or not treated at all.
• According to a report in Newsweek, 11/17/97, "Each new drug, with its attendant publicity, brings more men into the game. Some urologists expect the number of men seeking treatment to double in the coming years."
  

Incidence increases with age: About 5 percent of 40-year-old men and between 15 and 25 percent of 65-year-old men experience ED. But it is not an inevitable part of aging.

ED is treatable at any age, and awareness of this fact has been growing. More men have been seeking help and returning to normal sexual activity because of improved, successful treatments for ED.

Causes

The process of achieving an erection is complex and problems may occur for a variety of reasons. These problems can be psychological, physical, or a combination of the two. In older men, ED usually has a physical cause, such as disease, injury, or side effects of drugs. Any disorder that causes injury to the nerves or impairs blood flow in the penis has the potential to cause ED.

Physical causes of ED are related to a breakdown or damage to the sequence of events that lead to an erection. This sequence involves nerve impulses in the brain, spine, and penis as well as the subsequent response in the muscles, fibrous tissues, veins and arteries in and near the corpora cavernosa.

Often times the breakdown or damage in the sequence affects the arteries, muscles, and surrounding tissues of the penis, and this breakdown is most commonly the result of a disease. Diseases that commonly cause ED include:

• Diabetes: Diabetes, can cause nerve and artery damage that can make achieving an erection difficult. Between 35% and 50% of men with diabetes experience ED, according the National Institutes of Health. Some estimates are higher, stating that up to 75% of men with diabetes will experience at least some degree of ED during their lifetime and the risk increases with age.
• Kidney disease: Kidney disease can cause chemical changes to occur in your body that affect hormones, circulation, nerve function, and energy level. Often times these changes will lower a person's libido (sex drive) or sexual ability. Drugs used to treat kidney disease may also cause ED.
• Neurological (nerve and brain) diseases: The nervous system (the body's system of nerves) plays a vital part in achieving and maintaining an erection and it is common for men with diseases such as heart disease,  stroke, multiple sclerosis (MS), Alzheimer's disease, Parkinson's disease and spinal cord injuries to experience ED. This is due to an interruption in the transmission of nerve impulses between the brain and the penis.
• Prostate cancer : Prostate cancer doesn't cause ED on its own, but treatment (radiation, hormonal manipulation, or surgery to remove the cancer) can lead to erectile problems.
• Vascular disease: Vascular diseases are those that affect the blood vessels. These diseases include atherosclerosis (hardening of the arteries), hypertension, and high cholesterol. These diseases, which account for 70% of physically-related causes of ED, all restrict blood flow to the heart, the brain and, in the case of ED, the penis.

The physical causes of ED are not only disease-related. There are many other potential causes, including

• Injury: Injuries to the pelvis, bladder, spinal cord, and penis that require surgery also commonly cause ED.
• Hormonal imbalances: Imbalances of hormones, such as thyroid hormones, prolactin, and testosterone, can affect a man's response to sexual stimulation. These imbalances can be the result of a tumor of the pituitary gland, kidney disease, liver disease, or hormonal treatment of prostate cancer.
• Prescription drugs : There are over 200 types of prescription drugs that may cause ED. These include many  common medicines—blood pressure drugs, antihistamines, antidepressants, tranquilizers, appetite suppressants, and cimetidine (an ulcer drug)—can produce ED as a side effect.
• Prostate enlargement: Bladder neck obstruction due to prostate enlargement has recently been implicated in being associated with varying degrees of ED.
• Surgery: Surgery performed to treat diseases such as prostate cancer and bladder cancer often require the removal of nerves and tissues around the affected area which can lead to ED. Some of these surgeries result in only temporary problems (lasting 6-18 months) while others result in permanent damage to the nerves and tissue around the penis and require treatment in order for an erection to be achieved.
• Venous leak: If the veins in the penis cannot prevent blood from leaving the penis during an erection, an erection cannot be maintained. This is known as a venous leak, and can be a result of injury or disease.
• Tobacco, alcohol or drug use: All three of these substances can damage a person's blood vessels and/or restrict blood flow to the penis, causing ED. Smoking in particular plays a large role in causing ED in people with arteriosclerosis.

Patient History
Medical and sexual histories help define the degree and nature of ED. A medical history can disclose diseases that lead to ED, while a simple recounting of sexual activity might distinguish among problems with sexual desire, erection, ejaculation, or orgasm.

Using certain prescription or illegal drugs can suggest a chemical cause, since drug effects account for 25 percent of ED cases. Cutting back on or substituting certain medications can often alleviate the problem.

Physical Examination
A physical examination can give clues to systemic problems. For example, if the penis is not sensitive to touching, a problem in the nervous system may be the cause. Abnormal secondary sex characteristics, such as hair pattern or breast enlargement, can point to hormonal problems, which would mean that the endocrine system is involved. The examiner might discover a circulatory problem by observing decreased pulses in the wrist or ankles. And unusual characteristics of the penis itself could suggest the source of the problem—for example, a penis that bends or curves when erect could be the result of Peyronie's disease.

Laboratory Tests
Several laboratory tests can help diagnose ED. Tests for systemic diseases include blood counts, urinalysis, lipid profile, and measurements of creatinine and liver enzymes. Measuring the amount of free testosterone in the blood can yield information about problems with the endocrine system and is indicated especially in patients with decreased sexual desire.

Other Tests
Monitoring erections that occur during sleep (nocturnal penile tumescence) can help rule out certain psychological causes of ED. Healthy men have involuntary erections during sleep. If nocturnal erections do not occur, then ED is likely to have a physical rather than psychological cause. Tests of nocturnal erections are not completely reliable, however. Scientists have not standardized such tests and have not determined when they should be applied for best results.

Psychosocial Examination
A psychosocial examination, using an interview and a questionnaire, reveals psychological factors. A man's sexual partner may also be interviewed to determine expectations and perceptions during sexual intercourse.

There are many treatment options today for ED. The options will depend upon the cause and the individuals specific situation.

• Lifestyle Changes. For some men, making a few healthy lifestyle changes may solve the problem. Quitting smoking, losing excess weight, and increasing physical activity may help some men regain sexual function.
• Psychotherapy and Behavior Modifications. Psychotherapy and behavior modifications in selected patients are considered next if indicated. Experts often treat psychologically based ED using techniques that decrease the anxiety associated with intercourse. The patient's partner can help with the techniques, which include gradual development of intimacy and stimulation. Such techniques also can help relieve anxiety when ED from physical causes is being treated.
• Review of Medicines. Cutting back on any drugs with harmful side effects if applicable is the next option. For example, drugs for high blood pressure work in different ways. If you think a particular drug is causing problems with erection, tell your doctor and ask whether you can try a different class of blood pressure medicine.
• Drug Therapy. Drugs for treating ED may also be a prescribed treatment method. In March 1998, the Food and Drug Administration (FDA) approved Viagra, the first pill to treat ED. Since that time, vardenafil hydrochloride (Levitra) and tadalafil (Cialis) have also been approved. Viagra, Levitra, and Cialis all belong to a class of drugs called phosphodiesterase (PDE) inhibitors. Taken an hour before sexual activity, these drugs work by enhancing the effects of nitric oxide, a chemical that relaxes smooth muscles in the penis during sexual stimulation and allows increased blood flow. None of these PDE inhibitors should be used more than once a day. Men who take nitrate-based drugs such as nitroglycerin for heart problems should not use either drug because the combination can cause a sudden drop in blood pressure. Also, tell your doctor if you take any drugs called alpha-blockers, which are used to treat prostate enlargement or high blood pressure. Your doctor may need to adjust your ED prescription. Taking a PDE inhibitor and an alpha-blocker at the same time (within 4 hours) can cause a sudden drop in blood pressure.
• Hormonal Therapy. Oral testosterone can reduce ED in some men with low levels of natural testosterone, but it is often ineffective and may cause liver damage.
• Injectable Drugs. Many men achieve stronger erections by injecting drugs into the penis, causing it to become engorged with blood. Drugs such as papaverine hydrochloride, phentolamine, and alprostadil (marketed as Caverject) widen blood vessels. These drugs may create unwanted side effects, however, including persistent erection (known as priapism) and scarring. Nitroglycerin, a muscle relaxant, can sometimes enhance erection when rubbed on the penis. A system for inserting a pellet of alprostadil into the urethra is marketed as Muse. The system uses a prefilled applicator to deliver the pellet about an inch deep into the urethra. An erection will begin within 8 to 10 minutes and may last 30 to 60 minutes. The most common side effects are aching in the penis, testicles, and area between the penis and rectum; warmth or burning sensation in the urethra; redness from increased blood flow to the penis; and minor urethral bleeding or spotting.  Research on drugs for treating ED is expanding rapidly. Patients should ask their doctor about the latest advances.
• Other Drug Therapy. Patients also have claimed that other oral drugs—including dopamine and serotonin agonists, and trazodone—are effective, but the results of scientific studies to substantiate these claims have been inconsistent. Improvements observed following use of these drugs may be examples of the placebo effect, that is, a change that results simply from the patient's believing that an improvement will occur.
• Herbal  Therapy. Patients also have claimed that other herbs oral drugs—including yohimbinebark, horney goat weed, and vitamins, such as DMAE—are effective, but the results of scientific studies to substantiate these claims have been inconsistent.
• Other Options. They may include vacuum devices, and surgically implanted devices. In rare cases, surgery involving veins or arteries may be considered.
  

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