What is erectile dysfunction (ED)?

Impotence, or erectile dysfunction (ED), may result from the total inability to achieve erection, an inconsistent ability to achieve an erection, or the ability to only sustain a brief erection. According to the National Institutes of Health (NIH), 15 million to 30 million men are affected by ED, depending on the definition used.

Although in the past it was commonly believed to be due to psychological problems, it is now known that 80 percent to 90 percent of impotence is caused by physical problems, usually related to the blood supply of the penis. Many advances have occurred in both diagnosis and treatment of ED.

What are the risk factors for ED?

According to the American Urological Association, as men age, the level of circulating testosterone decreases, which may interfere with normal erection. While a low testosterone level itself is rarely the cause of ED (5 percent or less), low testosterone can be an additional contributing factor in many men who have other risk factors for ED. Other risk factors for ED include various medical problems such as hypertension (abnormally high blood pressure), diabetes, vascular disease, and high levels of blood cholesterol. Smoking and drug and alcohol abuse also are risk factors for ED.

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 ingestion
• lack of sexual knowledge
• poor sexual techniques
• inadequate interpersonal relationships
• many chronic diseases, especially renal failure and dialysis
• smoking, which accentuates the effects of other risk factors such as vascular disease or hypertension

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 is a learned behavior that begins when a male first becomes sexually active (as opposed to organic or physical) impotence. 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 or anxiety.



• 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.



• venous leak - Venous leak may be caused when the veins in the penis cannot prevent blood from leaving the penis during erection. This may be congenital or result from damage to the veins of the penis.



• diabetes - Impotence is common in persons with diabetes. There are 8.7 million adult men in the US with diabetes, and it is estimated that 35 percent to 50 percent 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 persons 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, anti-anxiety 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 body-builders, too much or too little thyroid hormone, and hormones administered for prostate cancer may cause impotence. Rarely is low testosterone responsible for impotence.



• Peyronie's disease
  Peyronie's disease is a rare inflammatory condition that causes scarring of erectile tissue that may result in curvature of the penis. This condition can impair sexual function.

How is ED diagnosed?
The American Urological Association states that for most men, a diagnosis will require a simple medical history, physical examination, and a few routine blood tests. Most patients do not require extensive testing before beginning treatment.

Diagnostic procedures for ED may include the following:

• patient medical/sexual history - may reveal conditions or diseases that lead to impotence and helps 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.


• lab tests - to help diagnose impotence 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 - to help reveal psychological factors. The sexual partner also may be interviewed to determine expectations and perceptions encountered during sexual intercourse.

Treatment for ED:

Specific treatment for erectile dysfunction will be determined by your physician 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 the following:

• medical treatments



• sildenafil citrate (Viagra^®)
  Viagra^® is 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 and may last up to 36 hours.

The U.S. Food and Drug Administration (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 physician 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 be able to 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 form and as a skin patch.



• penile implants
  There are three types of implants used to treat ED, including the following:



• 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 non-erect 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.

Coping with ED:
Erectile dysfunction can cause strain on a couple. Many times, men will avoid sexual situations due to their 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 for 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, men should tell their physicians about their symptoms of ED. Physicians may ask directly about sexual function, through conversation or a questionnaire during a check-up, in order to detect more serious health conditions sooner.

Active lifestyle may lower man's risk of sexual inability: Researchers are finding that, when it comes to sexual ability, exercise can make a difference. The study, published in the journal Urology, is one of a few that connects a sedentary lifestyle with impotence, demonstrating once again the health benefits of exercise.

In the study, researchers wanted to determine whether lifestyle had an effect on a man's sexual ability, particularly on middle-aged men - those between the ages of 40 and 70 years of age. The study's authors analyzed the data from nearly 600 men who had participated in the Massachusetts Male Aging Study.

At the study's initial stage, the researchers analyzed the lifestyle habits and health of the participating men. At this time, none of the men had been diagnosed with erectile dysfunction, heart disease, or diabetes.

Eight years later, the researchers evaluated the same men, analyzing any changes with their lifestyle, in comparison to any problems with erectile dysfunction. It was found that half of the men who smoked had now quit and that half of the heavy drinkers - those drinking more than three alcoholic drinks a day - had reduced their alcohol intake.

Eighteen percent of the men who were then considered obese had lost weight, and slightly over half of the men once considered sedentary were now consistently exercising and burning at least 200 calories a day through physical activity. It was also found that 17 percent of the men suffered from erectile dysfunction.

What made an impact in regards to sexual dysfunction?

The researchers found that the higher number of those suffering from sexual dysfunction were the men who had been obese at the study's initial stages. The researchers also found that the men with the sedentary lifestyle at the study's follow-up had a higher incidence of erectile dysfunction, regardless of their activity level when the study initially started eight years ago.

In terms of smoking and heavy drinking, no connection leading to an increased risk of erectile dysfunction was found, making it obvious to the researchers that weight and physical activity played stronger roles when it comes to impotence.

The researchers also discovered that the greatest risk of impotence was among the middle-aged men who had remained sedentary throughout the eight years of the study, as well as those who had gained weight.

When it comes to improving sexual ability, the good news is that exercise can make a difference no matter what age you start. The study indicates the risk of sexual inability is lowered with moderate, consistent exercise. But do not overdo it. The researchers also pointed out that the study participants doing the most intense exercise had a higher level of impotence than the men who moderately exercised.