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What is erectile dysfunction (ED)?

Impotence, or erectile dysfunction, is the inability to achieve an erection, and/or dissatisfaction with the size, rigidity, and/or duration of erections. According to the National Institutes of Health (NIH), erectile dysfunction affects up to 30 million men.

Although in the past it was commonly believed to be due to psychological problems, it is now known that for most men erectile dysfunction is caused by physical problems, usually related to the blood supply of the penis. Many advances have occurred in both diagnosis and treatment of erectile dysfunction.

What are the risk factors for erectile dysfunction?

According to the NIH, erectile dysfunction is also a symptom that accompanies many disorders and diseases.

Direct risk factors for erectile dysfunction may include the following:

• Prostate problems

• Type 2 diabetes

• Hypogonadism in association with a number of endocrinologic conditions

• Hypertension (high blood pressure)

• Vascular disease and vascular surgery

• High levels of blood cholesterol

• Low levels of HDL (high-density lipoprotein)

• Drugs

• Neurogenic disorders

• Peyronie's disease (distortion or curvature of the penis)

• Priapism (inflammation of the penis)

• Depression

• Alcohol use

• Lack of sexual knowledge

• Poor sexual techniques

• Inadequate interpersonal relationships

• Many chronic diseases, especially renal failure and dialysis

• Smoking, which exacerbates the effects of other risk factors, such as vascular disease or hypertension

Age appears to be a strong indirect risk factor in that it is associated with increased likelihood of direct risk factors, some of which are listed above.

It is estimated that about 4 percent of men in their fifties, and nearly 17 percent of men in their sixties, have difficulty achieving an erection. Accurate risk factor identification and characterization are essential for prevention or treatment of erectile dysfunction.

What are the different types (and causes) of ED?

The following are some of the different types and possible causes of impotence:

• Premature ejaculation (PE). Premature ejaculation is the inability to maintain an erection long enough for mutual satisfaction. Premature ejaculation is divided into primary and secondary forms:

  • Primary premature ejaculation. Primary premature ejaculation is a learned behavior that begins when a male first becomes sexually active. Like any learned behaviors, it can be unlearned. This form of primary PE is psychogenic (as opposed to organic or physical) impotence. (Congenital venous leak is a subset of primary PE and is caused by a congenital condition in which the venous drainage system in the penis does not shut down properly.)

  • Secondary premature ejaculation. Secondary premature ejaculation occurs when, after years of normal ejaculation, the duration of intercourse grows progressively shorter. Secondary PE is due to physical causes, usually involving the penile arteries, veins, or both.

  • Performance anxiety. Performance anxiety is a form of psychogenic impotence, usually caused by stress.

  • Depression. Depression is another cause of psychogenic impotence. Some antidepressant medications cause erectile failure.

  • Organic impotence. Organic impotence involves the penile arteries, veins, or both and is the most common cause of impotence, especially in older men. When the problem is arterial, it is usually caused by arteriosclerosis, or hardening of the arteries, although trauma to the arteries may be the cause. The controllable risk factors for arteriosclerosis--being overweight, lack of exercise, high cholesterol, high blood pressure, and cigarette smoking--can cause erectile failure often before progressing to affect the heart. Many experts believe that when veins are the cause, a venous leak, or cavernosal failure, is the most common vascular problem.

  • Diabetes. Impotence is common in people with diabetes. An estimated 10.9 million adult men in the U.S. have diabetes, and 35 to 50 percent of these men are impotent. The process involves premature and unusually severe hardening of the arteries. Peripheral neuropathy, with involvement of the nerves controlling erections, is commonly seen in people with diabetes.

  • Neurologic causes. There are many neurological (nerve problems) causes of impotence. Diabetes, chronic alcoholism, multiple sclerosis, heavy metal poisoning, spinal cord and nerve injuries, and nerve damage from pelvic operations can cause erectile dysfunction.

  • Drug-induced impotence. A great variety of prescription drugs, such as blood pressure medications, antianxiety and antidepressant medications, glaucoma eye drops, and cancer chemotherapy agents are just some of the many medications associated with impotence.

  • Hormone-induced impotence. Hormonal abnormalities, such as increased prolactin (a hormone produced by the anterior pituitary gland), steroid abuse by bodybuilders, too much or too little thyroid hormone, and hormones administered for prostate cancer may cause impotence. Rarely is low testosterone responsible for impotence.

How is ED diagnosed?

Diagnostic procedures for ED may include the following:

• Patient medical or sexual history. This may reveal conditions or diseases that lead to impotence and help distinguish among problems with erection, ejaculation, orgasm, or sexual desire.

• Physical examination. To look for evidence of systemic problems, such as the following:

  • A problem in the nervous system may be involved if the penis does not respond as expected to certain touching.

  • Secondary sex characteristics, such as hair pattern, can point to hormonal problems, which involve the endocrine system.

  • Circulatory problems could be indicated by an aneurysm.

  • Unusual characteristics of the penis itself could suggest the basis of the impotence.

• Laboratory tests. These can include blood counts, urinalysis, lipid profile, and measurements of creatinine and liver enzymes. When low sexual desire is a symptom, measurement of testosterone in the blood can yield information about problems with the endocrine system.

• Psychosocial examination. This is done to help reveal psychological factors that may be affecting performance. The sexual partner may also be interviewed to determine expectations and perceptions encountered during sexual intercourse.

What is the treatment for ED?

Specific treatment for erectile dysfunction will be determined by your doctor based on:

• Your age, overall health, and medical history

• Extent of the disease

• Your tolerance for specific medications, procedures, or therapies

• Expectations for the course of the disease

• Your opinion or preference

Some of the treatments available for ED include:

Medical treatments:

• Sildenafil citrate (Viagra). A prescription medication taken orally for the treatment of ED. Viagra does not directly cause penile erection, but affects the response to sexual stimulation.

• Vardenafil citrate (Levitra). In clinical studies, Levitra has been shown to work quickly and improve sexual function in men the first time they take the medication. It has been shown to work well in men of all ages, in men with diabetes, and in men who have had the surgical procedure called radical prostatectomy.

• Tadalafil citrate (Cialis). Studies have indicated that Cialis stays in the body longer than other medications in its class. Most men who take this medication find that an erection occurs within 30 minutes and the effects of the medication may last up to 36 hours.

  The FDA recommends that men follow general precautions before taking a medication for ED. Men who are taking medications that contain nitrates, such as nitroglycerin, should NOT use Viagra, Levitra, or Cialis. Taking nitrates with one of these medications can lower blood pressure too much. In addition, men who take Levitra or Cialis should not use alpha blockers, as they could result in hypotension (abnormally low blood pressure). Experts recommend that men have a complete medical history and physical examination to determine the cause of ED. Men should tell their doctor about all the medications they are taking, including over-the-counter medications.

  In addition, men should not take these medications if they have a history of heart attack or stroke, or if they have a bleeding disorder or stomach ulcers.

  Men with medical conditions that may cause a sustained erection, such as sickle cell anemia, leukemia, or multiple myeloma, or a man who has an abnormally-shaped penis, may not benefit from these medications. Also, men with liver diseases or a disease of the retina, such as macular degeneration or retinitis pigmentosa, may not be able to take these medications, or may need to take the lowest dosage.

  These medical treatments should NOT be used by women or children. Elderly men are especially sensitive to the effects of these medical treatments, which may increase their chance of having side effects.

Hormone replacement therapy

Testosterone replacement therapy may improve energy, mood, and bone density, increase muscle mass and weight, and heighten sexual interest in older men who may have deficient levels of testosterone. Testosterone supplementation is not recommended for men who have normal testosterone levels for their age group due to the risk of prostate enlargement and other side effects. Testosterone replacement therapy is available in an oral and injectable form, cream or gel, and as a skin patch.

Penile implants

Three types of implants are used to treat ED, including:

• Hydraulic pump. A pump and two cylinders are placed within the erection chambers of the penis, which causes an erection by releasing a saline solution; it can also remove the solution to deflate the penis.

• Prosthesis. Two semi-rigid but bendable rods are placed within the erection chambers of the penis, which allows manipulation into an erect or nonerect position.

• Interlocking soft plastic blocks. These are placed within the erection chambers of the penis and can be inflated or deflated using a cable that passes through them.

Infection is the most common cause of penile implant failure and is treatable with antibiotics. In some cases, the infected implant must be replaced by a new implant. Implants are usually not considered until other methods of treatment have been tried.

How do couples cope with ED?

Erectile dysfunction can cause strain on a couple. Many times, men will avoid sexual situations due to the emotional pain associated with ED, causing their partner to feel rejected or inadequate. It is important to communicate openly with your partner. Some couples consider seeking treatment for ED together, while other men prefer to seek treatment without their partner's knowledge. A lack of communication is the primary barrier for seeking treatment and can prolong the suffering. The loss of erectile capacity can have a profound effect on a man. The good news is that ED can usually be treated safely and effectively.

Feeling embarrassed about being impotent may prevent many men from seeking the medical attention they need, which can delay diagnosis and treatment of more serious underlying conditions. Impotence itself is often related to an underlying problem, such as heart disease, diabetes, liver disease, or other medical conditions.

Since impotence can be a forewarning symptom of progressive coronary disease, doctors should be more direct when questioning patients about their health. By asking patients more directly about their sexual function through conversation or a questionnaire during a checkup, doctors may be able to detect more serious health conditions sooner.