Drugs Expert

Erectile dysfunction (ED, “male impotence “) is a sexual dysfunction characterized by the inability to develop or maintain an erection of the penis sufficient for satisfactory sexual performance.

An erection occurs as a hydraulic effect due to blood entering and being retained in sponge-like bodies within the penis. The process is most often initiated as a result of sexual arousal, when signals are transmitted from the brain to nerves in the penis. Erectile dysfunction is indicated when an erection is difficult to produce. There are various circulatory causes, including alteration of the voltage-gated potassium channel as in the case of arsenic poisoning from drinking water. The most important organic causes are cardiovascular disease and diabetes, neurological problems (for example, trauma from prostatectomy surgery), hormonal insufficiencies (hypogonadism) and drug side effects.

Psychological impotence is where erection or penetration fails due to thoughts or feelings (psychological reasons) rather than physical impossibility; this is somewhat less frequent but often can be helped. Notably in psychological impotence, there is a strong response to placebo treatment. Erection, tied closely as it is about ideas of physical well being, can have severe psychological consequences.

Besides treating the underlying causes such as potassium deficiency or arsenic contamination of drinking water, the first line treatment of erectile dysfunction consists of a trial of PDE5 inhibitor drugs (the first of which was sildenafil or Viagra). In some cases, treatment can involve prostaglandin tablets in the urethra, intracavernous injections with a fine needle into the penis that cause swelling, a penile prosthesis, a penis pump or vascular reconstructive surgery.

The Latin term impotentia coeundi describes simple inability to insert the penis into the vagina. It is now mostly replaced by more precise terms. The study of erectile dysfunction within medicine is covered by andrology, a sub-field within urology.

What causes Erectile dysfunction?

The ability to achieve and sustain erections requires

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,
4. adequate levels of nitric oxide in the penis.

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

• 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, cardiovascular disease, 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 50-60 years of age. 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 increase the risk of erectile dysfunction in diabetes. In addition to atherosclerosis and/or neuropathy causing ED in diabetes, many men with diabetes also develop a myopathy (muscle disease) as their cause of ED in which the compliance of the muscles in the corpora cavernosa is decreased, and clinically this presents as an inability to maintain the erection.
• Hypertension (high blood pressure): People 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, those 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. High blood pressure also accelerates the progression of atherosclerosis, which in turn can contribute to erectile dysfunction. 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 for prostate cancer (prostatectomy), radiation to the prostate, surgery for benign prostatic enlargement, multiple sclerosis (a neurological disease with the potential to cause widespread damage to nerves), and long-term diabetes mellitus.
• Substance abuse: Marijuana, heroin, cocaine, methamphetamines, crystal meth, and alcohol abuse contribute to erectile dysfunction. Alcoholism, in addition to causing nerve damage, can lead to atrophy (shrinking) 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 propranolol (Inderal) or other beta-blockers, 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).
• Depression and anxiety: Psychological factors may be responsible for erectile dysfunction. These factors include stress, anxiety, guilt, depression, widower syndrome, low self-esteem, posttraumatic stress disorder, and fear of sexual failure (performance anxiety). It is also worth noting that many medications used for treatment of depression and other psychiatric disorders may cause erectile dysfunction or ejaculatory problems.

What are the Risk Factors?

As you get older, erections may take longer to develop and may not be as firm. You may need more direct touch to your penis to get and keep an erection. This isn’t a direct consequence of getting older. Usually it’s a result of underlying health problems or taking medications, which is more common as men age.

A variety of risk factors can contribute to erectile dysfunction. They include:

• Medical conditions, particularly diabetes or heart problems.
• Using tobacco, which restricts blood flow to veins and arteries. Over time tobacco use can cause chronic health problems that lead to erectile dysfunction.
• Being overweight, especially if you’re very overweight (obese).
• Certain medical treatments, such as prostate surgery or radiation treatment for cancer.
• Injuries, particularly if they damage the nerves that control erections.
• Medications, including antidepressants, antihistamines and medications to treat high blood pressure, pain or prostate cancer.
• Psychological conditions, such as stress, anxiety or depression.
• Drug and alcohol use, especially if you’re a long-term drug user or heavy drinker.
• Prolonged bicycling, which can compress nerves and affect blood flow to the penis — leading to temporary erectile dysfunction.

What are the Symptoms of Erectile dysfunction?

Erectile dysfunction is the inability to maintain an erection firm enough for sex, on an ongoing basis. Symptoms related to erectile dysfunction may include:

• Trouble getting an erection
• Trouble keeping an erection
• Reduced sexual desire

When to see a doctor
A family doctor is a good place to start when you have erectile problems. See your doctor if:

• Erectile or other sexual problems are an issue for you or your partner
• You have diabetes, heart disease or another known health problem that may be linked to erectile dysfunction
• You have other symptoms along with erectile dysfunction that may not seem related

Diagnosis

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 three 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 (for example, premature 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 may 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 (gynecomastia) 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 with painful erection could be the result of Peyronie’s disease. Particular attention is paid to any underlying risk factors for erectile dysfunction.

Laboratory tests

The following are common laboratory tests to evaluate erectile dysfunction:

• 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.
• Liver enzymes and liver function tests: Advanced liver disease (cirrhosis) can result in hormonal imbalance and gonad dysfunction leading to low testosterone levels. Thus, evaluation for liver disease may be necessary in cases of erectile dysfunction.
• Total testosterone levels: Blood samples for total testosterone levels should be obtained in the early morning (before 8 a.m.) 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.
• Other hormone levels: Measurement of other hormones beside testosterone (luteinizing hormone (LH), prolactin level, and cortisol level) may provide clues to other underlying causes of testosterone deficiency and erectile problems, such as pituitary disease or adrenal gland abnormalities. Thyroid levels may be routinely checked as both hypothyroidism and hyperthyroidism can contribute to erectile dysfunction.
• 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 blood tests: Evaluation for hemochromatosis, lupus, scleroderma, zinc deficiency, sickle cell anemia, cancers (leukemia, colon cancer) are some of the other potential tests that may be performed based on each individual’s history and symptoms.

Imaging tests

In a setting of a previous pelvic trauma, X-rays may be performed to assess various bony abnormalities. Ultrasound of the penis and testicles is done occasionally to check for testicular size and structural abnormalities. Ultrasound with Doppler imaging can provide additional information about blood flow of the penis. Rarely, an angiogram may be performed in cases in which possible vascular surgery could be beneficial.

Other tests

Prostaglandin E1 injection test is sometimes performed to determine the penile blood flow. Prostaglandin is directly injected into the corpora cavernosa in order to cause dilation of blood vessels and promote blood flow into the penis. If erection ensues, it confirms normal or adequate blood flow to the penis. This can also provide information about possible therapeutic options.

Monitoring erections that occur during sleep (nocturnal penile tumescence) can help distinguish between erectile dysfunction of psychological and physical causes. A band is worn around the penis for two to three successive nights and it can signal intensity and duration of erections if they occur. 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.

Direct vibrational stimulation (biothesiometry) is occasionally done to evaluate penile nerve function. Small electromagnetic electrodes are placed on the shaft of the penis and vibration amplitude is slightly adjusted until sensation is noted by the patient. Although this test does not measure the exact nerve function, it serves as a screening method to detect any sensory nerve deficit as the cause of ED.

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.

Methods of Treatment

The first thing your doctor will do is to make sure you’re getting the right treatment for any health problems that could be causing or worsening your erectile dysfunction.

A variety of options exist for treating erectile dysfunction. The cause and severity of your condition, and underlying health problems, are important factors in your doctor’s recommending the best treatment or treatments for you. Your doctor can explain the risks and benefits of each treatment, and will consider your preferences. Your partner’s preferences also may play a role in treatment choices.

Oral medications

Oral medications are a successful erectile dysfunction treatment for many men. They include:

• Sildenafil (Viagra)
• Tadalafil (Cialis)
• Vardenafil (Levitra)

All three medications work in much the same way. These drugs enhance the effects of nitric oxide, a natural chemical your body produces that relaxes muscles in the penis. This increases blood flow and allows you to get an erection in response to sexual stimulation. These medications vary in dosage, how long they work and their side effects. Your doctor will take into account your particular situation to determine which medication may work best.

Don’t expect these medications to fix your erectile dysfunction immediately. You may need to work with your doctor to find the right medication and dose for you.

Before taking any prescription erectile dysfunction medication (including over-the-counter supplements or herbal remedies), get your doctor’s OK. Although these medications can help many people, not all men should take them to treat erectile dysfunction. These medications may not work or may be dangerous for you if you:

• Take nitrate drugs for angina, such as nitroglycerin (Nitro-Bid, others), isosorbide mononitrate (Imdur) and isosorbide dinitrate (Isordil)
• Take a blood-thinning (anticoagulant) medication, alpha blockers for enlarged prostate (benign prostatic hyperplasia) or high blood pressure medications
• Have heart disease or heart failure
• Have had a stroke
• Have very low blood pressure (hypotension) or uncontrolled high blood pressure (hypertension)
• Have uncontrolled diabetes

Other medications

Other medications for erectile dysfunction include:

• Alprostadil self-injection. With this method, you use a fine needle to inject alprostadil (Alprostadil, Caverject Impulse, Edex) into the base or side of your penis. In some cases, medications generally used for other conditions are used for penile injections on their own or in combination. Examples include papaverine, alprostadil and phentolamine. Each injection generally produces an erection in five to 20 minutes that lasts about an hour. Because the needle used is very fine, pain from the injection site is usually minor. Side effects can include bleeding from the injection, prolonged erection and formation of fibrous tissue at the injection site.
• Alprostadil penis suppository. Alprostadil intraurethral (MUSE) therapy involves placing a tiny alprostadil suppository inside your penis. You use a special applicator to insert the suppository about two inches down into your penis. Side effects can include pain, minor bleeding in the urethra, dizziness and formation of fibrous tissue inside your penis.
• Testosterone replacement. Some men have erectile dysfunction caused by low levels of the hormone testosterone, and may need testosterone replacement therapy.

Penis pumps, surgery and implants

Medications may not work or may not be a good choice for you. If this is the case, your doctor may recommend a different treatment. Other treatments include:

• Penis pumps. A penis pump (vacuum constriction device) is a hollow tube with a hand-powered or battery-powered pump. The tube is placed over your penis, and then the pump is used to suck out the air inside the tube. This creates a vacuum that pulls blood into your penis. Once you get an erection, you slip a tension ring around the base of your penis to hold in the blood and keep it firm. You then remove the vacuum device. The erection typically lasts long enough for a couple to have sex. You remove the tension ring after intercourse.
• Penile implants. This treatment involves surgically placing devices into the two sides of the penis. These implants consist of either inflatable or semirigid rods made from silicone or polyurethane. The inflatable devices allow you to control when and how long you have an erection. The semirigid rods keep the penis firm but bendable. This treatment can be expensive and is usually not recommended until other methods have been tried first. As with any surgery, there is a risk of complications such as infection.
• Blood vessel surgery. In rare cases, a leaking blood vessel can cause erectile dysfunction and surgery is necessary to repair it.

Psychological counseling

If your erectile dysfunction is caused by stress, anxiety or depression, your doctor may suggest that you, or you and your partner, visit a psychologist or counselor. Even if it is caused by something physical, erectile dysfunction can create stress and relationship tension.

For many men, erectile dysfunction is caused or worsened by lifestyle choices. Here are some things you can do that may help:

• If you smoke, quit. If you have trouble quitting, get help. Try nicotine replacement (such as gum or lozenges), available over-the-counter, or ask your doctor about prescription medication that can help you quit.
• Lose weight. Being overweight can cause — or worsen — erectile dysfunction.
• Get regular exercise. This can help with underlying problems that play a part in erectile dysfunction in a number of ways, including reducing stress, helping you lose weight and increasing blood flow.
• Get treatment for alcohol or drug problems. Drinking too much or taking certain illicit drugs can worsen erectile dysfunction directly or by causing long-term health problems.
• Work through relationship issues. Improve communication with your partner and consider couples or marriage counseling if you’re having trouble working through problems on your own.

Alternative treatments

Several alternative treatments are used to treat erectile dysfunction, but more studies are needed to see whether they are safe or effective. Alternative treatments used for erectile dysfunction include:

• Acupuncture
• Korean red ginseng (Panax ginseng)
• Yohimbine
• DHEA (dehydroepiandrosterone), a hormone that’s a building block for testosterone
• Ginkgo
• L-arginine

While some of these supplements appear to be relatively safe, others are more risky and can interact with medications or cause other problems. Before using any supplement, OK it with your doctor to make sure it’s safe for you — especially if you have chronic health problems.

Herbal Viagra

Some alternative products that claim to work for erectile dysfunction can be dangerous. The Food and Drug Administration (FDA) has issued warnings about several types of “herbal Viagra” because they contain potentially harmful drugs not listed on the label. Some of these drugs can interact with prescription drugs and cause dangerously low blood pressure. These products are especially dangerous for men who take nitrates.

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Prevention

The best way to prevent erectile dysfunction is to make healthy lifestyle choices and to manage any existing health problems you have. Here are some things you can do:

• Work with your doctor to manage diabetes, heart disease or other chronic health problems.
• See your doctor for regular checkups and medical screening tests.
• Stop smoking, limit or avoid alcohol, and don’t use street drugs.
• Exercise regularly.
• Take steps to reduce stress.
• Get help for anxiety or depression.