Erectile Dysfunction

What is erectile dysfunction?

Erectile dysfunction (ED), also known as impotence, is the inability to achieve or sustain an erection for satisfactory sexual activity. Erectile dysfunction is different from other conditions that interfere with sexual intercourse, such as lack of sexual desire and problems with ejaculation and orgasm. This article focuses on the evaluation and treatment of erectile dysfunction.

How common is erectile dysfunction?

Erectile dysfunction (ED, impotence) varies in severity; some men have a total inability to achieve an erection, others have an inconsistent ability to achieve an erection, and still others can sustain only brief erections. The variations in severity of erectile dysfunction make estimating its frequency difficult. Many men also are reluctant to discuss erectile dysfunction with their doctors, and thus the condition is under-diagnosed. Nevertheless, experts have estimated that erectile dysfunction affects 30 million men in the Untied States.

While erectile dysfunction can occur at any age, it is uncommon among young men and more common in the elderly. By age 45, most men have experienced erectile dysfunction at least some of the time. According to the Massachusetts Male Aging Study, complete impotence increases from 5% among men 40 years of age to 15% among men 70 years and older. Population studies conducted in the Netherlands found that some degree of erectile dysfunction occurred in 20% of men between ages 50 to 54, and in 50% of men between ages 70 to 78. In 1999, the National Ambulatory Medical Care Survey counted 1,520,000 doctor-office visits for erectile dysfunction.

What is normal penis anatomy?

The penis contains two chambers, called the corpora cavernosa, which run the length of the upper side of the penis (see figure 1 below). The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa. Filling the corpora cavernosa is a spongy tissue consisting of smooth muscles, fibrous tissues, spaces, veins, and arteries. A membrane, called the tunica albuginea, surrounds the corpora cavernosa. Veins located in the tunica albuginea drain blood out of the penis.

How does erection occur?

Erection begins with sexual stimulation. Sexual stimulation can be tactile (for example, by touching the penis), or mental (for example, by having sexual fantasies). Sexual stimulation generates electrical impulses along the nerves going to the penis and causes the nerves to release nitric oxide, which in turn increases the production of cyclic GMP (cGMP) in the smooth muscle cells of the corpora cavernosa. The cGMP causes the smooth muscles of the corpora cavernosa to relax, and allow rapid blood flow into the penis. The in-coming blood fills the corpora cavernosa, making the penis expand.

How is erection sustained?

The pressure from the expanding penis compresses the veins (blood vessels that drain the blood out of the penis) in the tunica albuginea, helping to trap the blood in the corpora cavernosa, thereby sustaining erection. Erection is reversed when cGMP levels in the corpora cavernosa fall, causing the smooth muscles of the corpora cavernosa to contract, stopping the inflow of blood and opening veins that drain blood away from the penis. The levels of the cGMP in the corpora cavernosa fall because it is destroyed by an enzyme called phosphodiesterase type 5 (PDE5)

What are the causes of erectile dysfunction?

The ability to achieve and sustain erections require:

1. A healthy nervous system that conducts nerve impulses in the brain, spinal column, and penis,

2. Healthy arteries in and near the corpora cavernosa,

3. Healthy smooth muscles and fibrous tissues within the corpora cavernosa, and

4. Adequate levels of nitric oxide in the penis.

Erectile dysfunction can occur if one or more of these requirements are not met. The causes of erectile dysfunction include:

• Aging: There are two reasons why older men are more likely to experience erectile dysfunction than younger men. First, older men are more likely to develop diseases (such as heart attacks, angina, strokes, diabetes mellitus, and high blood pressure) that are associated with erectile dysfunction. Second, the aging process alone can cause erectile dysfunction in some men; primarily by decreasing the compliance of the tissues in the corpora cavernosa, although it has been suggested, but not proven, that there is also decreased production of nitric oxide in the nerves that innervate the corporal smooth muscle within the penis.
• Diabetes mellitus: Erectile dysfunction tends to develop 10-15 years earlier in diabetic men than among nondiabetic men. In a population study of men with type I diabetes for more than 10 years, erectile dysfunction was reported by 55% of men between the ages of 50 to 60 years. The increased risk of erectile dysfunction among men with diabetes mellitus may be due to the earlier onset and greater severity of atherosclerosis that narrows the arteries and thereby reduces the delivery of blood to the penis. When insufficient blood is delivered to the penis, it is not possible to achieve an erection.
  Diabetes mellitus also causes erectile dysfunction by damaging both sensory and autonomic nerves, a condition called diabetic neuropathy. Smoking cigarettes, obesity, poor control of blood glucose levels, and having diabetes mellitus for a long time further increases the risk of erectile dysfunction in diabetes. In addition to atherosclerosis and/or neuropathy causing ED in diabetes, many diabetic men develop a myopathy (muscle disease) as their cause of ED in which the compliance of the muscle in the corpora cavernosa is decreased and clinically this presents as an inability to maintain the erection.
• Hypertension (high blood pressure): Patients with essential hypertension or arteriosclerosis have an increased risk of developing erectile dysfunction. Essential hypertension is the most common form of hypertension; it is called essential hypertension because it is not caused by another disease, (for example, by kidney disease). It is not clearly known how essential hypertension causes erectile dysfunction; however, patients with essential hypertension have been found to have low production of nitric oxide by the arteries of the body, including the arteries in the penis. Scientists now suspect that the decreased levels of nitric oxide in patients with essential hypertension may contribute to erectile dysfunction.
• Cardiovascular diseases: The most common cause of cardiovascular diseases in the United States is atherosclerosis, the narrowing and hardening of arteries that reduces blood flow. Atherosclerosis typically affects arteries throughout the body and is aggravated by hypertension, high blood cholesterol levels, cigarette smoking, and diabetes mellitus. When coronary arteries (arteries that supply blood to the heart muscle) are narrowed by atherosclerosis, heart attacks and angina occur. When cerebral arteries (arteries that supply blood to the brain) are narrowed by atherosclerosis, strokes occur. Similarly, when arteries to the penis and the pelvic organs are narrowed by atherosclerosis, insufficient blood is delivered to the penis to achieve an erection. There is a close correlation between the severity of atherosclerosis in the coronary arteries and erectile dysfunction. For example, men with more severe coronary artery atherosclerosis also tend to have more erectile dysfunction than men with mild or no coronary artery atherosclerosis. Some doctors suggest that men with new onset erectile dysfunction should be evaluated for silent coronary artery diseases (advanced coronary artery atherosclerosis that has not yet caused angina or heart attacks).
• Cigarette smoking: Cigarette smoking aggravates atherosclerosis and thereby increases the risk for erectile dysfunction.
• Nerve or spinal cord damage: Damage to the spinal cord and nerves in the pelvis can cause erectile dysfunction. Nerve damage can be due to disease, trauma, or surgical procedures. Examples include injury to the spinal cord from automobile accidents, injury to the pelvic nerves from prostate surgery, multiple sclerosis (a neurological disease with the potential to cause widespread damage to nerves), and long-term diabetes mellitus.
• Substance abuse: Marijuana, heroin, cocaine, and alcohol abuse contribute to erectile dysfunction. Alcoholism, in addition to causing nerve damage, can lead to atrophy of the testicles and lower testosterone levels.
• Low testosterone levels: Testosterone (the primary sex hormone in men) is not only necessary for sex drive (libido) but also is necessary to maintain nitric oxide levels in the penis. Therefore, men with hypogonadism (diminished function of the testes resulting in low testosterone production) can have low sex drive and erectile dysfunction.
• Medications: Many common medicines produce erectile dysfunction as a side effect. Medicines that can cause erectile dysfunction include many used to treat high blood pressure, antihistamines, antidepressants, tranquilizers, and appetite suppressants. Examples of common medicines that can cause erectile dysfunction include beta-blockers such as propranolol (Inderal), hydrochlorothiazide, digoxin (Lanoxin), amitriptyline (Elavil), famotidine (Pepcid), cimetidine (Tagamet), metoclopramide (Reglan), indomethacin (Indocin), lithium (Eskalith; Lithobid), verapamil (Calan, Verelan, Isoptin), phenytoin (Dilantin), and gemfibrozil (Lopid). For more, please visit the Medications Index.
• Depression and anxiety: Psychological factors may be responsible for erectile dysfunction. These factors include stress, anxiety, guilt, depression, low self-esteem, and fear of sexual failure.

How is erectile dysfunction diagnosed?

Patient history

A diagnosis of erectile dysfunction is made in men who have repeated inability to achieve and/or maintain an erection for satisfactory sexual performance for at least 3 months. Candid communication between the patient and the doctor is important in establishing the diagnosis of erectile dysfunction, assessing its severity, and determining the cause. During patient interviews, doctors try to answer the following questions:

1. Is the patient suffering from erectile dysfunction or from loss of libido or a disorder of ejaculation?

2. Is erectile dysfunction due to psychological or physical factors? Healthy men have involuntary erections in the early morning and during REM sleep (a stage in the sleep cycle with rapid eye movements). Men with psychogenic erectile dysfunction (erectile dysfunction due to psychological factors such as stress and anxiety rather than physical factors) usually maintain these involuntary erections. Men with physical causes of erectile dysfunction (for example; atherosclerosis, smoking, and diabetes) usually do not have these involuntary erections.

3. Are there physical causes of erectile dysfunction? A prior history of cigarette smoking, heart attacks, strokes, and poor circulation in the extremities suggest atherosclerosis as the cause of the erectile dysfunction. Diminished sensation of the penis and the testicles, bladder dysfunction, and decreased sweating in the lower extremities suggest diabetic nerve damage. Loss of sexual desire and drive, lack of sexual fantasies, gynecomastia (enlargement of breasts), and diminished facial hair suggest low testosterone levels.

4. Is the patient taking medications that can contribute to erectile dysfunction?

Physical examination

The physical examination can reveal clues for physical causes of erectile dysfunction. For example, if the penis does not respond as expected to touching, a problem in the nervous system may be the cause. Small testicles, lack of facial hair and enlarged breasts can point to hormonal problems such as hypogonadism with low testosterone levels. A reduced flow of blood as a result of atherosclerosis can sometimes be diagnosed by finding diminished arterial pulses in the legs or listening with a stethoscope for bruits (the sound of blood flowing through narrowed arteries). Unusual characteristics of the penis itself could suggest the root of the erectile dysfunction, for example, bending of the penis during erection could be the result of Peyronie’s disease.

Laboratory tests

Common laboratory tests to evaluate erectile dysfunction include:

• Complete blood counts
• Urinalysis: An abnormal urinalysis may be a sign of diabetes mellitus and kidney damage
• Lipid profile: High levels of LDL cholesterol (bad cholesterol) in the blood promotes atherosclerosis.
• Blood glucose levels: Abnormally high blood glucose levels may be a sign of diabetes mellitus.
• Blood Hemoglobin A 1c: Abnormally high levels of blood hemoglobin A 1c in patients with diabetes mellitus establish that there is poor control of blood glucose levels.
• Serum creatinine: An abnormal serum creatinine may be the result of kidney damage due to diabetes.
• Total testosterone levels: Blood samples for total testosterone levels should be obtained in the early morning (before 8 am) because of wide fluctuations in the testosterone levels throughout the day. A low total testosterone level suggests hypogonadism. Measurement of bio-available testosterone may be a better measurement than total testosterone, especially in obese men and men with liver disease, but measurement of bio-available testosterone is not widely available.
• PSA levels: PSA (prostate specific antigen) blood levels and prostate examination to exclude prostate cancer is important before starting testosterone treatment since testosterone can aggravate prostate cancer.

Other tests

Monitoring erections that occur during sleep (nocturnal penile tumescence) can help distinguish between erectile dysfunction of psychological and physical causes. If nocturnal erections do not occur, then the cause of erectile dysfunction is likely to be physical rather than psychological, however, tests of nocturnal erections are not completely reliable. Scientists have not standardized the tests and have not determined in whom they should be done.

Psychosocial examination

A psychosocial examination using an interview and questionnaire may reveal psychological factors contributing to erectile dysfunction. The sexual partner also may be interviewed to determine expectations and perceptions encountered during sexual intercourse.

Traditional Medical Approaches to Erectile Dysfunction

Treatments for erectile dysfunction include:

1. Working with doctors to select medications that do not impair erectile function,

2. Making life style improvements (for example; quitting smoking, and exercising more),

3. Drugs such as sildenafil (Viagra), vardenafil (Levitra) or tadalafil (Cialis),

4. Inserting medications into the urethra (intraurethral suppositories),

5. Injecting medications into the corpora cavernosae (intracavernosal injections),

6. Vacuum constrictive devices for the penis,

7. Penile prostheses, and

8. Psychotherapy.

Adjusting medications

Many common medications for treating hypertension, depression, and high blood lipids can contribute to erectile dysfunction (see above). Treatment of hypertension is an example. There are many different types (classes) of anti-hypertensive medications (medications that lower blood pressure); these include beta-blockers, calcium channel blockers, diuretics (medications that increase urine volume), angiotensin converting enzyme inhibitors (ACE inhibitors), and angiotensin receptor blockers (ARBs). Anti-hypertensives may be used alone or in combination(s) to control blood pressure. Different classes of anti-hypertensives have different effects on erectile function. Inderal (a beta blocker) and hydrochlorothiazide (a diuretic) are known to cause erectile dysfunction, while calcium channel blockers and ACE inhibitors do not seem to affect erectile function. On the other hand, angiotensin receptor blockers (ARBs) such as losartan (Cozaar) and valsartan (Diovan), may actually increase sexual appetite, improve sexual performance, and decrease erectile dysfunction. Therefore, choosing an optimal anti-hypertensive combination is an important part of treating erectile dysfunction

Lifestyle improvements

Quitting smoking, exercising regularly, losing excess weight, curtailing excessive alcohol consumption, controlling hypertension, and optimizing blood glucose levels in patients with diabetes are not only important for maintaining good health but also may improve erectile function. Some studies suggest that men who have made lifestyle improvements experience increased rates of success with oral medications.

What is sildenafil (Viagra)?

Sildenafil (Viagra) was the first oral phosphodiesterase type 5 (PDE5) inhibitor approved by the FDA in the United States for the treatment of erectile dysfunction (it is not approved for women). Sildenafil inhibits PDE5, which is an enzyme that destroys cGMP. By inhibiting the destruction of cGMP by PDE5, sildenafil allows cGMP to accumulate. The cGMP in turn prolongs relaxation of the smooth muscle of the corpora cavernosa. Relaxation of the corpora cavernosa smooth muscle allows blood to flow into the penis resulting in increased engorgement of the penis. In short, sildenafil increases blood flow into the penis and decreases blood flow out of the penis.

What are the side effects of sildenafil (Viagra)?

The reported side effects of sildenafil (Viagra) include headache, flushing, nasal congestion, nausea, dyspepsia, diarrhea, and abnormal vision (seeing a bluish hue or brightness).

Sildenafil can cause hypotension (abnormally low blood pressure that can lead to fainting and even shock) when given to patients who are taking nitrates. Therefore, patients taking nitrates daily, even patients taking nitrates only once a day, should not take sildenafil. Nitrates are used most commonly to relieve angina (chest pain due to insufficient blood supply to the heart muscle because of narrowing of the coronary arteries); these include nitroglycerine tablets, patches, ointments, sprays, and pastes, as well as isosorbide dinitrate, and isosorbide mononitrate. Other nitrates such as amyl nitrate and butyl nitrate also are found in some recreational drugs called “poppers”.

Sildenafil should be used cautiously in men on alpha blockers such as doxazosin (Cardura), terazosin (Hytrin), and tamsulosin (Flomax). There have been occasional reports of low blood pressure in men who have taken the two classes of drugs simultaneously and therefore it is recommended that there be at least a span of 4-6 hours between the ingestion of sildenafil and alpha blockers.

There have been rare reports of priapism (prolonged and painful erections lasting more than 6 hours) with the use of PDE5 inhibitors such as sildenafil, vardenafil, and tadalafil, especially when sildenafil is used in combination with injection of medications into the corpora cavernosa or intraurethral suppositories. Patients with blood cell diseases such as sickle cell anemia, leukemia, and multiple myeloma have higher than normal risks of developing priapism. Priapism untreated can cause injury to the penis and lead to permanent impotence. Therefore, sildenafil should not be used in combination with intraurethral suppositories and corpora cavernosa injections.

What is vardenafil (Levitra)?

Vardenafil (Levitra) was the second oral medicine approved by the United FDA in the US for the treatment of erectile dysfunction. Like sildenafil (Viagra), vardenafil (Levitra) inhibits PDE5 which destroys cGMP (as discussed earlier).

What are the side effects of vardenafil (Levitra)?

The reported side effects of vardenafil (Levitra) include headache, flushing, nasal congestion, dyspepsia, body aches, dizziness, nausea, and increased blood levels of the muscle enzyme creatine kinase.

There have been rare reports of priapism (prolonged and painful erections lasting more than 6 hours) with the use of oral PDE5 inhibitors such as vardenafil, sildenafil and tadalafil. Patients with blood cell diseases such as sickle cell anemia, leukemia, and multiple myeloma have higher than normal risks of developing priapism. Priapism untreated can cause injury to the penis tissue and lead to permanent loss of potency. If there is prolonged erection (longer than 4 hours), immediate medical assistance should be sought.

There is insufficient information on the safety of vardenafil in men with the following conditions:

• Unstable angina (chest pain due to coronary artery disease that occurs at rest or with minimal physical exertion)
• Low blood pressure (a resting systolic blood pressure less than 90mm Hg)
• Uncontrolled high blood pressure (greater than 170/110 mm Hg)
• Recent stroke or heart attack (within 6 months)
• Uncontrolled, potentially life-threatening abnormal heart rhythms
• Severe liver disease
• Severe kidney failure requiring dialysis
• Severe heart failure or disease of the heart’s valves, for example, aortic stenosis
• Retinitis pigmentosa

Therefore, men with these conditions should not use vardenafil without having these conditions evaluated and stabilized first. For example, men with uncontrolled high blood pressure should have their blood pressure controlled; and men with potentially life-threatening abnormal heart rhythms should have these rhythms controlled.

When there is angina or heart failure, the doctor may need to determine whether the heart has enough reserve to safely carry out the work necessary for sexual activity by performing cardiac treadmill stress testing.

What is tadalafil (Cialis)?

Tadalafil (Cialis) is the third oral medicine approved by the United FDA in the US for the treatment of erectile dysfunction. Like sildenafil (Viagra) and vardenafil (Levitra), tadalafil inhibits PDE5.

What are the side effects of tadalafil (Cialis)?

The most common side effects of tadalafil (Cialis) include headache, indigestion, back pain, muscle aches, facial flushing, and nasal congestion.

Back pain and muscle aches occurred in less than 7% of patients, and usually occurred at 12 to 24 hours after taking tadalafil. The back pain and muscle aches associated with tadalafil were characterized by mild to moderate muscle discomfort in the lower back, buttocks and thighs, often aggravated by lying down. The back and muscle aches resolved in most patients without treatment within 48 hours. When treatment was necessary, acetaminophen (Tylenol) and non-steroidal antiinflammatory drugs (NSAIDs) such as Motrin, Advil, or Aleve were effective. Approximately 0.5% of all the patients using tadalafil discontinued the drug due to back pain or muscle aches.

Reports of abnormal vision were rare, it occurred in less than 0.1% of patients using tadalafil.

There have been rare reports of priapism (prolonged and painful erections lasting more than 6 hours) with the use of oral PDE5 inhibitors such as vardenafil, sildenafil and tadalafil. Patients with blood cell diseases such as sickle cell anemia, leukemia, and multiple myeloma have higher than normal risks of developing priapism. Priapism untreated can cause injury to the penile tissue and lead to permanent loss of potency. If there is prolonged erection (longer than 4 hours), immediate medical assistance should be sought.

Tadalafil is not recommended for men with the following conditions:

• Unstable angina (chest pain due to coronary artery disease that occurs at rest or with minimal physical exertion)
• Low blood pressure (a resting systolic blood pressure less than 90mm Hg)
• Uncontrolled high blood pressure (greater than 170/110 mm Hg)
• Recent stroke or heart attack (within 6 months)
• Uncontrolled, potentially life-threatening abnormal heart rhythms
• Severe liver disease
• Severe heart failure or disease of the heart’s valves, for example, aortic stenosis
• Retinitis pigmentosa

Therefore, men with these conditions should not use tadalafil without having these conditions evaluated and stabilized first. For example, men with uncontrolled high blood pressure should have their blood pressure controlled; and men with potentially life-threatening abnormal heart rhythms should have these rhythms controlled.

When there is angina or heart failure, the doctor may need to determine whether the heart has enough reserve to safely carry out the work necessary for sexual activity by performing cardiac treadmill stress testing.

It is no wonder, after reviewing these alternatives, that men have sought the assistance of Mother Nature throughout the centuries in his search for sexual bliss. Natural herbal formulas can and do work just as effectively as the above remedies.

Are natural treatments effective ?

In many cases, sexual dysfunction or sluggish sexual responses may be caused by poor systemic health, stress, the build up of toxins and unhealthy lifestyles.

In a way, sexual health can be seen as a sort of ‘barometer’ of overall systemic and psychological health. Men who are healthy, fit and confident about themselves and about life usually report a vigorous and satisfying sex life, no matter what their age.

Practitioners of Chinese and Ayurvedic medicine, African herbalists and traditional healers from a wide range of cultures have many centuries of knowledge regarding the use of herbal medicines to treat a wide variety of medical problems and to promote optimum health and functioning.

In this respect, certain herbs have been identified as having strong aphrodisiac properties and the ability to improve sexual functioning and overall systemic health.

Recent studies have shown that many of these herbs have the ability to improve peripheral and systemic blood flow and to act as vasodilators, leading to increased blood flow to the penis and erectile tissue and therefore heightened sexual pleasure and performance.

In the correct dosage, certain herbs have also been shown to stimulate adrenal glands, improve endocrine and male hormonal functioning, boost stamina and vitality, increase libido and improve the health and functioning of the sexual organs, especially the prostate, penis and urethral systems.

To view our list of natural products and guides related to Erectile Dysfunction click HERE