Erectile dysfunction, sometimes called "impotence," is the repeated inability to get or keep an erection firm enough for sexual intercourse. The word "impotence" may also be used to describe other problems that interfere with sexual intercourse and reproduction, such as lack of sexual desire and problems with ejaculation or orgasm. Using the term erectile dysfunction makes it clear that those other problems are not involved.
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. Estimates range from 15 million to 30 million, depending on the definition used. According to the National Ambulatory Medical Care Survey (NAMCS), for every 1,000 men in the United States, 7.7 physician office visits were made for ED in 1985. By 1999, that rate had nearly tripled to 22.3. The increase happened gradually, presumably as treatments such as vacuum devices and injectable drugs became more widely available and discussing erectile function became accepted. Perhaps the most publicized advance was the introduction of the oral drug sildenafil citrate (Viagra) in March 1998. NAMCS data on new drugs show an estimated 2.6 million mentions of Viagra at physician office visits in 1999, and one-third of those mentions occurred during visits for a diagnosis other than ED.
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. 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. Urologists, who specialize in problems of the urinary tract, have traditionally treated ED, however, urologists accounted for only 25 percent of Viagra mentions in 1999.
How does an erection occur?
The penis contains two chambers called the corpora cavernosa, which run the length of the organ (see figure 1). A spongy tissue fills the chambers. The corpora cavernosa are surrounded by a membrane, called the tunica albuginea. The spongy tissue contains smooth muscles, fibrous tissues, spaces, veins, and arteries. The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa and is surrounded by the corpus spongiosum.
Erection begins with sensory or mental stimulation, or both. Impulses from the brain and local nerves cause the muscles of the corpora cavernosa to relax, allowing blood to flow in and fill the spaces. The blood creates pressure in the corpora cavernosa, making the penis expand. The tunica albuginea helps trap the blood in the corpora cavernosa, thereby sustaining erection. When muscles in the penis contract to stop the inflow of blood and open outflow channels, erection is reversed.
Two drawings of the penis: the top one showing the arteries of the penis and the bottom one showing the veins of the penis. The top drawing contains labels for the cavernous artery, dorsal artery, corpora cavernosa, bulbourethral artery, and corpus.
Figure 1. Arteries (top) and veins (bottom) penetrate the long, filled cavities running the length of the penis-the corpora cavernosa and the corpus spongiosum. Erection occurs when relaxed muscles allow the corpora cavernosa to fill with excess blood fed by the arteries, while drainage of blood through the veins is blocked.
What causes erectile dysfunction (ED)?
Since an erection requires a precise sequence of events, ED can occur when any of the events is disrupted. The sequence includes nerve impulses in the brain, spinal column, and area around the penis, and response in muscles, fibrous tissues, veins, and arteries in and near the corpora cavernosa.
Damage to nerves, arteries, smooth muscles, and fibrous tissues, often as a result of disease, is the most common cause of ED. Diseases-such as diabetes, kidney disease, chronic alcoholism, multiple sclerosis, atherosclerosis, vascular disease, and neurologic disease-account for about 70 percent of ED cases. Between 35 and 50 percent of men with diabetes experience ED.
Lifestyle choices that contribute to heart disease and vascular problems also raise the risk of erectile dysfunction. Smoking, being overweight, and avoiding exercise are possible causes of ED.
Also, surgery (especially radical prostate and bladder surgery for cancer) can injure nerves and arteries near the penis, causing ED. Injury to the penis, spinal cord, prostate, bladder, and pelvis can lead to ED by harming nerves, smooth muscles, arteries, and fibrous tissues of the corpora cavernosa.
In addition, many common medicines-blood pressure drugs, antihistamines, antidepressants, tranquilizers, appetite suppressants, and cimetidine (an ulcer drug)-can produce ED as a side effect.
Experts believe that psychological factors such as stress, anxiety, guilt, depression, low self-esteem, and fear of sexual failure cause 10 to 20 percent of ED cases. Men with a physical cause for ED frequently experience the same sort of psychological reactions (stress, anxiety, guilt, depression). Other possible causes are smoking, which affects blood flow in veins and arteries, and hormonal abnormalities, such as not enough testosterone.
How is ED diagnosed?
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. The International Index of Erectile function (IIEF) is a useful questionnaire to assess the severity of the problem.
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.
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.
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 and related hormones in the blood can yield information about problems with the endocrine system and is indicated especially in patients with decreased sexual desire.
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.
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.
How is ED treated?
Most physicians suggest that treatments proceed from least to most invasive. 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.
Cutting back on any drugs with harmful side effects is considered next. 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.
Psychotherapy and behaviour modifications in selected patients are considered next if indicated, followed by oral or locally injected drugs, vacuum devices, and surgically implanted devices. In rare cases, surgery involving veins or arteries may be considered.
Good nutrition may help improve impotence.
- Eat more fruit, vegetables, whole grains, soy, beans, seeds, nuts, olive oil, and cold-water fish (salmon, tuna, sardines, halibut, and mackerel).
- Eat less dairy products, refined food, fried foods, hydrogenated oils, alcohol and caffeine.
- Bioflavonoids - 1000 mg daily.
- Flaxseed meal - grind and eat 2-4 tbsp daily. An alternative is to take 1 tbsp of flaxseed oil daily. Flaxseed oil is also a good source of the essential fatty acid alpha-linolenic acid (an omega-3 fatty acid).
- Inositol hexaniacinate - 1000-3000 mg daily to improve circulation and lower cholesterol. Diabetics should not take this supplement.
- Selenium - 200 mcg daily.
- Vitamin C - 1000 mg daily.
- Vitamin E - 400 IU daily.
- Zinc - 30 mg daily.
- Ginseng - traditionally used for male impotence, although no current studies support this usage.
- Ginkgo biloba - increases arterial blood flow.
- Damiana - traditionally used as an aphrodisiac although again there are no current studies to confirm its effectiveness.
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.
Viagra, Levitra, and Cialis all belong to a class of drugs called phosphodiesterase (PDE5) 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.
Viagra - is the best-known drug in the PDE5 family and has the advantage of being available in 3 doses (25, 50 &,,,,,, 100 mg). Its absorption is delayed by alcohol and fat in the stomach.
Levitra - (10 or 20 mg) has a reputation for having the fastest onset of action and fewer side-effects.
Cialis - (10 or 20 mg) lasts for 2 days and so improves spontaneity. Cialis 5mg once a day was released in the UK in march 2009. Its use is indicated for patients who are already responders to PDE inhibitors that require more than two uses of PDE inhibitor a week.
The following patients should not take these drugs:-
- Men taking cardiac nitrates drugs (for chest pain) and/or a blockers (used to treat high blood pressure and BPH).
- Men who have had a heart attack or stroke within the past 6 months.
- Men with uncontrolled high or low blood pressure, liver disease or unstable angina).
None of these PDE inhibitors should be used more than once a day.
Oral testosterone can reduce ED in some men with low levels of natural testosterone, but it is often ineffective and may cause liver damage. Patients also have claimed that other oral drugs-including yohimbine hydrochloride, 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.
While oral medicines improve the response to sexual stimulation, they do not trigger an automatic erection as injections do. Many men achieve stronger erections by injecting drugs into the penis, causing it to become engorged with blood. Drugs such alprostadil (Caverject) widen blood vessels. These drugs may create unwanted side effects, however, including persistent erection (known as priapism) and scarring.
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.
Mechanical vacuum devices cause erection by creating a partial vacuum, which draws blood into the penis, engorging and expanding it. The devices have three components: a plastic cylinder, into which the penis is placed, a pump, which draws air out of the cylinder, and an elastic band, which is placed around the base of the penis to maintain the erection after the cylinder is removed and during intercourse by preventing blood from flowing back into the body.
One variation of the vacuum device involves a semirigid rubber sheath that is placed on the penis and remains there after erection is attained and during intercourse.
Surgery usually has one of three goals:
- to implant a device that can cause the penis to become erect
- to reconstruct arteries to increase flow of blood to the penis
- to block off veins that allow blood to leak from the penile tissues
Implanted devices, known as prostheses, can restore erection in many men with ED. Possible problems with implants include mechanical breakdown and infection, although mechanical problems have diminished in recent years because of technological advances.
Malleable implants usually consist of paired rods, which are inserted surgically into the corpora cavernosa. The user manually adjusts the position of the penis and, therefore, the rods. Adjustment does not affect the width or length of the penis.
Inflatable implants consist of paired cylinders, which are surgically inserted inside the penis and can be expanded using pressurised fluid. Tubes connect the cylinders to a fluid reservoir and a pump, which are also surgically implanted. The patient inflates the cylinders by pressing on the small pump, located under the skin in the scrotum. Inflatable implants can expand the length and width of the penis somewhat. They also leave the penis in a more natural state when not inflated.
Surgery to repair arteries can reduce ED caused by obstructions that block the flow of blood. The best candidates for such surgery are young men with discrete blockage of an artery because of an injury to the crotch or fracture of the pelvis. The procedure is almost never successful in older men with widespread blockage.
Surgery to veins that allow blood to leave the penis usually involves an opposite procedure-intentional blockage. Blocking off veins (ligation) can reduce the leakage of blood that diminishes the rigidity of the penis during erection. However, experts have raised questions about the long-term effectiveness of this procedure, and it is rarely done