Title: impotence (Erectile Dysfunction) , impotence (Erectile Dysfunction), Jun2002
WHAT IS impotence (ERECTILE DYSFUNCTION)?
impotence is the inability to achieve or maintain an erection sufficiently rigid for sexual intercourse, ejaculation, or both. Sexual drive and the ability to have an orgasm are not necessarily affected. Because all men experience erection problems from time to time, doctors consider impotence to be present if attempts at intercourse fail on at least 25% of attempts.
impotence is not new in medicine or human experience, but it is not easily or openly discussed. Cultural expectations of male sexuality inhibit many men from seeking help for a disorder that can, in most cases, benefit from medical treatment. The term “ impotence ” comes from Latin and means loss of power; a more accurate term is “erectile dysfunction.” The condition is normal and usually temporary, so it is highly unfortunate that the common term for it implies a sweeping diminution in a man’s overall capabilities.
The Structure of the Penis. The penis is composed of the following structures:
- Two parallel columns of spongy tissue called the corpus cavernosa , or erectile bodies.
- A central spongy chamber called the corpus spongiosum , which contains the urethra, the tube that carries urine from the bladder through the penis.
These structures are made up of erectile tissue . Erectile tissue is rich in tiny pools of blood vessels called cavernous sinuses . Each of these vessels are surrounded by smooth muscles and supported by elastic fibrous tissue composed of a protein called collagen.
Erectile Function. The penis is either flaccid or erect depending on the state of arousal. In the flaccid, or unerect, penis, the following normally occurs:
- Small arteries leading to the cavernous sinuses contract, reducing the inflow of blood.
- The smooth muscles regulating the many tiny blood vessels also stay contracted, limiting the amount of blood that can collect in the penis.
During arousal the following occurs:
- The man’s central nervous system stimulates the release of a number of chemicals, including nitric oxide.
- Nitric oxide stimulates production of cyclic GMP, a chemical that relaxes the smooth muscles in the penis. This allows blood to flow into the tiny pool-like cavernous sinuses, flooding the penis.
- This increased blood flow nearly doubles the diameter of the spongy chambers.
- The veins surrounding the chambers are squeezed almost completely shut by this pressure.
- The veins are unable to drain blood out of the penis and so the penis becomes rigid and erect.
- After ejaculation or arousal, cyclic GMP is broken down by an enzyme called phosphodiesterase-5 (PDE5), and other compounds are released that cause the penis to become flaccid (unerect) again.
A proper balance of certain chemicals, gases, and other substances is critical for erectile health:
Collagen. The protein collagen is the major component in structural tissue in the body, including in the penis. Excessive amounts, however, form scar tissue, which can impair erectile function.
Oxygen. Oxygen-rich blood is one of the most important components for erectile health. Oxygen affects two substances that are important in achieving erection:
- Oxygen suppresses transforming growth factor beta 1 (TGF-B1). TGF-B1 is a component of the immune system called a cytokine and is produced by smooth muscle cells. It appears to stimulate collagen production in the corpus cavernosum, which can lead to erectile dysfunction.
- Oxygen enhances the activity of prostaglandin E1. Prostaglandin E1 is produced during erection by the muscle cells in the penis. It activates an enzyme that initiates calcium release by the smooth muscle cells, which relaxes them and allows blood flow. Prostaglandin E1 also suppresses production of collagen.
Oxygen levels vary widely from reduced levels in the flaccid state to very high in the erect state. During sleep, oxygen levels are high and a man can normally have three to five erections per night, each one lasting from 20 to 40 minutes.
Testosterone and Other Hormones. Normal levels of hormones, especially testosterone, are essential for erectile function, though their exact role is not clear.
Erectile dysfunction most commonly occurs when the penis is deprived of oxygen-rich blood. When oxygen levels to the penis are low, an imbalance occurs in two important substances, TGF-B1 and prostaglandin E1:
- TGF-B1 levels increase, which trigger production of collagen, a tough protein that forms all types of connective tissue, including scar tissue.
- In addition, there is a reduction in prostaglandin E1, a chemical that suppresses collagen production and relaxes the smooth muscles to allow blood flow resulting in an erection.
When TGF-B1 levels increase and prostaglandin E1 levels decrease, smooth muscles waste away and collagen is overproduced, causing scarring, loss of elasticity, and reduced blood flow to the penis. A number of conditions can deprive the penis of oxygen-rich blood.
Blockage of Blood Vessels (Ischemia). The primary cause of oxygen deprivation is ischemia, the blockage of blood vessels. The same conditions that cause blockage in the blood vessels leading to heart problems may also contribute to erectile dysfunction. For example, when cholesterol and other factors are imbalanced, a fatty substance called plaque forms on artery walls. As the plaque builds up, the arterial walls gradually narrow, reducing blood flow. This process, known as atherosclerosis, is the major contributor to the development of coronary heart disease. It may also play a role in the development of erectile dysfunction.
A large survey in 2000 suggested that nearly 620,000 American men between ages 40 and 70 experience erectile dysfunction of any degree each year, and an estimated 20 million and 30 million men in the US have erectile dysfunction at some point during their lives.
Being older is primarily associated with impotence in most men. At a major professional meeting in 2000, experts reported survey results finding that 44% of men over age 50 experienced some degree of erectile dysfunction, but less than a quarter of them discussed their problems with a physician. Many felt this was simply an aging problem. Nevertheless, impotence is not inevitable with age. In another survey of men over 60 years old, 61% reported being sexually active, and nearly half derived as much if not more emotional benefit from their sex lives as they did in their 40s.
Severe erectile dysfunction in elderly men often has more to do with disease than age itself. For example heart disease, diabetes, and hypertension can cause sexual dysfunction and are more likely to occur in older than younger men.
So many physical and psychological situations can cause erectile dysfunction, in fact, that a man should consider brief periods of impotence to be as normal as having a cold. In fact, a cold is one common condition that can cause temporary impotence . It is safe to say, then, that every man experiences erectile dysfunction from time to time. [ See What Are Lifestyle and Psychological Factors Contributing to Erectile Dysfunction?and What are the Physical Causes of impotence ?.]
Differentiating between Physical and Psychological Causes of Erectile Dysfunction
Over the past decades, the medical perspective on the causes of impotence has shifted. Common wisdom used to attribute almost all cases of impotence to psychological factors. Now investigators estimate that up to 85% of impotence cases are caused by medical or physical problems. Only 15% are psychologically based.
It is often difficult to determine if the cause of erectile dysfunction is a physical or psychological one, or even some combination. The following may be helpful:
- Physical impotence can be caused by internal medical causes (e.g., diabetes, high blood pressure) or by external causes (e.g., surgery, injury, medications). Erectile dysfunction due to medical conditions usually develops gradually but continuously over a period of time. If impotence persists over a three-month period and is not due to a stressful event, drug use, alcohol, or known medical conditions, then the patient needs medical attention by a urologist specializing in impotence .
- Psychological impotence tends to develop rapidly and be related to a recent situation or event. The patient may be able to have an erection in some circumstances but not in others. Being able to experience or maintain an erection upon waking up in the morning suggests that the problem is psychological rather than physical.
It should be strongly noted that in virtually every case of impotence there are emotional issues that can seriously affect the man’s self-esteem and relationships. Negative emotions may even perpetuate erectile dysfunction that has been caused by a medical condition that has been successfully treated. Many men tend to fault themselves for their impotence even if it is clearly caused by physical problems over which they have little or no control.
Emotional Disorders Associated with Erectile Dysfunction
Anxiety. Anxiety has both emotional and physical consequences that can affect erectile function. It is among the most frequently cited contributors to psychological impotence . Excessive concern about sexual performance is often referred to as performance or “honeymoon” anxiety and may provoke an intense fear of failure and self-doubt. It can sometimes set off a cycle of chronic impotence . In response to anxiety, the brain releases chemicals known as neurotransmitters that constrict the smooth muscles of the penis and its arteries. This constriction reduces the blood flow into and increases the blood flow out of the penis. Even simple stress may promote the release of brain chemicals that disrupt potency in a similar way.
Depression. Depression is strongly associated with erectile dysfunction. In one study, 82% of men who reported moderate to severe erectile dysfunction also had symptoms of depression. Depression can certainly reduce sexual desire, but it is often not clear which condition came first.
Problems in Relationships
Troubles in relationships often have a direct impact on sexual functioning. Partners of men with erectile dysfunction may feel rejected and resentful, particularly if the affected man does not confide his own anxieties or depression. Both partners commonly experience guilt for what they each perceive as a personal failure. Tension and anger frequently arise between people who are unable to discuss sexual or emotional issues with each other. It can be very difficult for the man to perform sexually when both partners harbor negative feelings.
Socioeconomic Issues
Losing a job or having lower income or education increases the risk for impotence .
Smoking
Smoking contributes to the development of impotence , mainly because it compounds the effects of other disorders of the blood vessels, including high blood pressure and atherosclerosis. For example, a 2001 study concluded that among men with high blood pressure, smoking causes a 26-fold increase in erectile dysfunction.
Alcohol
Alcohol has also been implicated in causing impotence . A small amount releases inhibitions, but having more than one drink can depress the central nervous system and impair sexual function.
Lack of Frequent Erections
Infrequent erections deprive the penis of oxygen-rich blood. Without daily erections, collagen production increases and eventually may form a tough tissue that interferes with blood flow. The spontaneous erections men have while sleeping or awake may be a natural protection against this process.
Common Medical Conditions That Contribute to Erectile Dysfunction
Diabetes. Diabetes may contribute to as many as 40% of impotence cases . Between one-third and one-half of all diabetic men report some form of sexual difficulty. Atherosclerosis and nerve damage are both common complications of diabetes; when the blood vessels or nerves of the penis are involved, erectile dysfunction can result.
High Blood Pressure. Erectile dysfunction is more common and more severe in men with hypertension than it is in the general population. Many of the drugs used to treat hypertension are thought to cause impotence as a side effect; in these cases, it is reversible when the drugs are stopped. More recent evidence is suggesting, however, that the disease process that causes hypertension itself is the major cause of erectile dysfunction in these men. Newer anti-hypertensive agents, including angiotensin-converting enzyme (ACE) inhibitors and angiotensin-receptor blockers (ARBs) are less likely to cause erectile dysfunction. In fact, ARBs may be particularly effective in restoring erectile function in men with high blood pressure who suffer from impotence .
Parkinson’s Disease. As a risk factor for impotence , Parkinson’s disease (PD) is an under-appreciated problem. It is estimated that about one-third of men with PD experience impotence . The physical cause of PD-related impotence is most likely an impaired nervous system. Depression and lowered self-esteem also contribute to erectile dysfunction in these patients.
Multiple Sclerosis. Multiple sclerosis (MS), which affects the central nervous system, also precipitates sexual dysfunction in as many as 78% of male patients. (Corticosteroids, which are common treatments for MS, may improve sexual function.)
Diseases that Affect the Arteries. Because erectile dysfunction is often due to blockage of oxygen in the arteries that effect the penis, other diseases that are caused by arterial blockage are associated with erectile dysfunction. They include coronary artery, peripheral artery disease, and stroke.
Other Common Medical Conditions. Other medical conditions that have been associated with erectile dysfunction in some cases include allergies, thyroid problems, lung disease, and epilepsy.
Prostate Cancer and Its Treatments
Advanced prostate cancer can damage nerves needed for erectile function. Prostate surgery and surgical and radiation treatments for prostate cancer can also cause impotence . [ See Well-Connected Report #33, Prostate Cancer.]
Prostate Cancer Surgery (Radical Prostatectomy). The first nationally representative study to evaluate long-term outcomes after radical prostatectomy concluded that impotence occurs far more frequently than previously reported. The study included more African American, Hispanic, and young men than previously studied, although there was little difference among ethnic groups. About 40% of the study subjects considered sexual impairment a moderate to big problem, but over 70% still said they would have the surgery again. Patients reported postoperative impotence at the following rates depending on procedure:
A number of treatments for sexual dysfunction are available that may help some men. [See treatment sections.]
Radiation. The side effects of radiation therapy include most of those of surgery, but the risks for impotence and incontinence are considerably lower. A 2000 study concluded that adjuvant external-beam radiation therapy (given right after surgery) in moderate doses does not increase the risk for long-term urinary incontinence or sexual dysfunction beyond that of surgery alone (60% to 70%). An alternative radiation technique called brachytherapy, which involves the implantation of radioactive “seeds,” carries a lower impotence rate (roughly 40%). A 2000 study suggested that the dose of radiation received by the bulb of the penis correlates with risk of impotence . If this is confirmed by further study, carefully designed radiation may improve current rates.
Drug Treatments. Prostate cancer medical treatments commonly employ androgen-suppressive treatments, which cause erectile dysfunction.
Surgical Treatments that Affect Intestinal Tracts
Surgery for Colon and Rectal Cancers. Surgical and radiation treatments for colorectal cancers can cause impotence in some patients. For example, a 2001 study of rectal cancer patients treated with high-dose preoperative radiation followed by surgery and intraoperative radiotherapy reported that sexual function was impaired in about half of the patients. [ See Well-Connected Report #55, Colon and Rectal Cancers.]
Surgical Treatment of Inflammatory Bowel Disease. Rectal excision for inflammatory bowel disease can cause impotence , but rates are low (2% to 4%).
Operations for Fistulas. Surgery to repair anal fistulas can effect the muscles that control the rectum (external anal sphincter muscles), sometimes causing impotence . (Repair of these muscles may restore erectile function.)
Treatments for Benign Prostatic Hyperplasia (BPH)
Surgery and drug treatments for benign prostatic hyperplasia (BPH) can also increase the risk for impotence , although to a much lesser degree than surgery for prostate cancer.
- Between 4% and 10% of patients who have transurethral resection of the prostate (TURP) and open prostatectomy for BPH report impotence afterward. The risk is very low, however, in men who were functioning normally before surgery.
- Finasteride (Proscar) has been associated with impotence in between 6% and 19% of patients. Anti-androgen agents used to treat BPH can also cause erectile dysfunction.
Medications
About a quarter of all cases of impotence can be attributed to medications. Many drugs pose a risk for erectile dysfunction. Some authorities go so far as to say that nearly every drug, prescription or nonprescription, can be a cause of temporary erectile dysfunction.
Among the drugs that are common causes of impotence are the following:
- Drugs used in chemotherapy.
- Many drugs taken for high blood pressure, particularly diuretics and beta-blockers.
- Most drugs used for psychological disorders, including anti-anxiety drugs, anti-psychotic drugs, and antidepressants, especially selective serotonin reuptake inhibitors (SSRIs). Newer antidepressants pose fewer problems.
Drugs that sometimes cause impotence include:
- Older anti-ulcer medications (cimetidine).
- Anticholinergic drugs (including some antihistamines).
- Antinausea agents, particularly metoclopramide (Reglan).
- Antifungal drugs (especially ketoconazole).
Physical Trauma, Stress, or Injury
Injury to the Spine. Spinal cord injury and pelvic trauma, such as a pelvic fracture, can cause nerve damage that results in impotence . Other conditions that can injure the spine and effect impotence include spinal cord tumors, spina bifida, and a history of polio.
Bicycling. Studies have indicated that frequent bicycling may pose a risk for erectile dysfunction by reducing blood flow to the penis. The greatest risk is in cyclers who sit upright while cycling.
Note: Vasectomy doesnot cause erectile dysfunction. When impotence occurs after this procedure, it is often in men whose female partners were unable to accept the operation.
Hormonal Abnormalities
Hypogonadism (Testicular Failure). Hypogonadism in men is a deficiency in male hormones, usually due to an abnormality in the testicles, which secrete these hormones. It affects four to five million men in the United States. In addition to impotence , hypogonadism causes reductions in energy, sex drive, lean body mass, and bone density. Hypogonadism can be caused by a number of different conditions. Among them are the following:
- Disorders in the pituitary or hypothalamus glands.
- Malnutrition.
- Genetic factors.
- Myotonic dystrophy.
- Orchitis (inflammation of the testicles).
- Physical injury.
- Mumps.
- Radiation treatments.
- Exercise-induced hypogonadism. Only a few cases of exercise-induced hypogonadism have been identified in men, but some researchers believe certain athletes may be at risk, including those who began endurance training before full sexual maturity, have very low body weight, and have a history of stress fractures.
Low Testosterone Levels. Only about 5% of men who see a physician about erectile dysfunction have low levels of testosterone, the primary male hormone. In general, lower testosterone levels appear to reduce sexual interest, not cause impotence . A 1999 study, however, suggests that testosterone levels are not an accurate reflection of sexual drive.
Other Hormonal Abnormalities. Other hormonal abnormalities that can lead to erectile dysfunction include:
- High levels of the female hormone estrogen (which may occur in men with liver disease).
- Abnormalities of the pituitary gland that cause high levels of the hormone prolactin are particularly likely to cause impotence .
- Other, uncommon hormonal causes of impotence include an underactive or overactive thyroid or adrenal gland abnormalities.
Varicoceles
A varicocele is an enlarged (varicose) vein in the cord that connects to the testicle. Varicoceles are found in 15% to 20% of all men and in 25% to 40% of infertile men. When varicoceles occur in both testicles, they may contribute to hormone imbalances that cause erectile dysfunction.
impotence can be a symptom of serious medical conditions, such as atherosclerosis, diabetes, and hypertension. It can also indicate injury, age-related changes in tissue, or long-term effects of smoking, heavy drinking, or unhealthy diet.
Psychological effects can be significant. Erectile dysfunction can have a devastating impact on a relationship and can cause extreme depression, which may become chronic if not treated. When a consistent pattern of sexual dysfunction extends over a prolonged period of time, a serious physical or emotional disorder may be present.
Physician Interview
The physician typically interviews the patient about many physical and psychological factors. The patient must be as frank as possible for his physician to make a diagnosis. He should not interpret these questions as intrusive or too personal if he expects to obtain help. These questions are very relevant and important for determining the proper approach. Even when erectile dysfunction has a clear physical cause, relationships and psychological factors can also have an effect.
Medical and Personal History. The physician should take a medical and personal history and may ask about the following:
- Past and present medical problems.
- Medications or drugs being used.
- Any history of psychological problems, including stress, anxiety, or depression.
Sexual History. In addition the physician will ask about the patient’s sexually history, which may include the following:
- The nature of the onset of the dysfunction.
- The frequency, quality, and duration of any erections, and whether they occur at night or in the morning.
- The specific circumstances when erectile dysfunction occurred.
- Details of technique.
- The patient’s motivation for and expectations of treatment.
- Whether problems exist in the current relationship.
Interviewing the Sexual Partner. If appropriate, the physician might also interview the sexual partner. In fact, including the partner in the interview process may help the physician to better decipher underlying causes and in turn better recommend treatment choices.
Physical Examination
The physician should perform a careful physical exam, including examination of the genital area and a digital rectal examination (the doctor inserts a gloved and lubricated finger into the patient’s rectum) to check for prostate abnormalities.
Trials Using Treatments for Erectile Function
A useful approach is to administer a treatment for erectile dysfunction and then observe the response: Physicians now usually recommend a trial of sildenafil (Viagra) to test for an erection response after 30 to 60 minutes. This drug is replacing more invasive and expensive tests, such as an injection of papaverine or prostaglandin E1, medications that dilate blood vessels in the penis. They produce an erection in about 15 minutes.
After administering the treatment and waiting the appropriate amount of time, the physician then observes the erectile response, curvature of the penis, and response after erection, sometimes using an ultrasound scanner to assess blood flow.
Laboratory Tests
Blood Tests for Hormonal Abnormalities. Blood tests may be used to measure testosterone levels and, if necessary, prolactin levels to determine if there are hormone problems. The physician may also screen for thyroid and adrenal gland dysfunction. In addition, various specific tests for erectile dysfunction can be performed.
Tests for Medical Conditions that may be Causing Erectile Dysfunction. Evidence of other medical conditions should be sought, particularly hypertension, diabetes, atherosclerosis, and nerve damage.
Monitoring Nighttime Erections
Tests that monitor nighttime erections may be used to determine if the causes of erectile dysfunction are more likely to be psychological. Neither of the following methods is helpful in determining a physical cause for erectile dysfunction.
Snap-Gauge Test. The snap-gauge test monitors the man’s ability to achieve an erection during sleep. It is a very simple test.
- When the man goes to bed, he places bands around the shaft of his penis.
- If one or more breaks during the course of the night, it provides evidence of an erection. In this case, a psychological basis for the erectile dysfunction is likely.
RigiScan Monitor. A more sophisticated and more expensive device is the RigiScan monitor, which makes repetitive measurements of rigidity around the base and tip of the penis. This test is quite accurate but may fail to detect mild cases of erectile dysfunction.
Penile Brachial Index
The penile brachial index is a measurement that compares blood pressure in the penis with the blood pressure taken in the arm. Problems with the arterial flow to the penis can be detected using this method.
Imaging Techniques
Imaging tests may be used in certain cases, but they are expensive and often limited to younger men. Anyone considering these tests should have them done in a specialized setting by professionals experienced in their use.
Dynamic Infusion Cavernosometry and Cavernosography. Dynamic infusion cavernosometry and cavernosography (DICC) is usually only given to young men in whom some blockage of the penis or physical injury of the pelvic area is suspected. After an erection is induced with drugs, the following four steps are taken:
- The penile brachial index is taken.
- The storage ability of the penis is gauged.
- An ultrasound of the penile arteries is performed.
- An x-ray of the erect penis is taken.
Unfortunately, this test and other similar imaging techniques used to determine blood flow in the penis are currently not very effective or accurate in diagnosing and determining treatment.
Duplex Doppler Ultrasound. An ultrasound technique called duplex Doppler ultrasound may be useful alone or with sildenafil (Viagra) in detecting some causes of erectile dysfunction, such as leakage from blood vessels.
Approach to Treatment
The cause of impotence dictates the mode of treatment. The first step is to define the cause, if possible, and then try the simplest and least-risky solution.
Before a certain treatment is prescribed, the following factors should be considered:
- Any pre-existing illnesses and medications.
- The degree of comfort with the treatment method.
- Partner satisfaction and safety profiles need to be considered. Experts strongly recommend that the patient’s partner be involved to help with any necessary sexual adjustment.
No matter what the treatment, embarking on a healthy lifestyle is the first and critical step for maintaining and restoring erectile function.
Treatment Choices
Psychotherapies. Some form of psychological, behavioral, sexual, or combination therapy is often recommended for individuals suffering from impotence , regardless of cause.
Medical and Surgical Treatments. Sildenafil (Viagra), the first effective oral agent for erectile dysfunction, is currently the treatment of choice for many men.
Those who cannot or choose not to take the drug still have many other options, including the following:
- Medications inserted or injected into the penis.
- Vacuum devices.
- Intracavernosal injection therapy.
- Invasive procedures, such as penile implants or surgery (limited to those for whom other treatments haven’t worked and who have been carefully screened).
Ultimately, how successful the medical treatment is and how well it is accepted depends, in large part, on the man’s expectations and how he and his partner both adapt to the procedure.
Maintain General Health
Because many cases of impotence are due to reduced blood flow from blocked arteries, it is important to maintain the same lifestyle habits as those who face an increased risk for heart disease.
Diet. Everyone should eat a diet rich in fresh fruits and vegetables, whole grains, and fiber and low in saturated fats and sodium. Because erectile dysfunction is often related to circulation problems, diets that benefit the heart are especially important. [For more information, see the Well-Connected Report #43,Heart Healthy Diet. ]
Exercise. A regular exercise program is extremely important. One study reported that older men who ran 40 miles a week boosted their testosterone levels by 25% compared to their inactive peers. Another study found that men who burned 200 calories or more a day in physical activity (which can be achieved by two miles of brisk walking) cut their risk of erectile dysfunction by half compared to men who did not exercise.
Limit Alcohol and Quit Smoking. Men who drink alcohol should do so in moderation. Quitting smoking is essential.
Stay Sexually Active
Staying sexually active can help prevent impotence . Frequent erections stimulate blood flow to the penis. It may be helpful to note that erections are firmest during deep sleep right before waking up. Autumn is the time of the year when male hormone levels are highest and sexual activity is most frequent.
Kegel Exercises
The Kegel exercise is a simple exercise commonly used by people who have urinary incontinence and by pregnant women. It may also be helpful for men whose erectile dysfunction is caused by impaired blood circulation. The exercises consist of tightening and releasing the pelvic muscle that controls urination:
- Since the muscle is internal and is sometimes difficult to isolate, practice first while urinating. (Once learned, however, Kegel exercises should not be regularly performed while urinating because doing them at that time may eventually weaken the muscles.)
- Try to contract the muscle until the flow of urine is slowed or stopped. Attempt to hold each contraction for 10 seconds.
- Then release the muscle.
- Perform about 5 to 15 contractions three to five times daily.
It may be several months before the patient sees significant improvement.
Changing or Reducing Medications
If medications are causing impotence , the patient and physician should discuss alternatives or reduced dosages.
Psychotherapy and Behavioral Therapy
Even if erectile dysfunction is caused by a physical problem, interpersonal, supportive, or behavioral therapy can be of help to a patient during all phases of the decision-making process regarding possible methods of treatment. Therapy may also ease the adjustment period after the initiation or completion of treatment. It is beneficial to have the partner involved in this process. The value of sex therapy is questionable. In one study, 12 out of 20 men whose dysfunction had a psychological basis and who were advised to enter a sex clinic resisted sex therapy out of embarrassment or because they felt it wouldn’t help. Of the eight who entered therapy, only one actually achieved satisfactory sex.
Sildenafil (Viagra)
Sildenafil (Viagara) was originally developed for heart disease but was found to have a unique mechanism of action that targeted factors specific to the penis. The drug blocks the enzyme phosphodiesterase-5 (PDE5). This action maintains persistent levels of cyclic GMP, a chemical that is produced in the penis during sexual arousal and which is the primary chemical that relaxes smooth muscles and increases blood flow.
Good Candidates for Sildenafil. Sildenafil (Viagra) is now prescribed in over 90% of erectile dysfunction cases. It is a good choice for any man in good health who does not have conditions that preclude taking it. Studies indicate that overall, it may help more than 70% of patients achieve sexual function, with results depending, however, on individual conditions. It should be noted that other good options are still available for many men who do not respond to sildenafil.
Studies are indicating that sildenafil is safe and effective for many men whose erectile dysfunction is related to the following conditions:
- Hormonal problems or psychologically induced impotence . These men achieve the highest success rates (80% to 100%). Furthermore, in one study, among men with mild to moderate depression who responded to the drug, symptoms of depression eased in 76% of them.
- Stable heart disease, with symptoms responsive to drug therapy, but who are not taking nitrates.
- Controlled diabetes (type 1 or 2). Success rates in one study were 69%.
- Controlled hypertension.
- Kidney conditions, including those that require chronic dialysis and kidney transplantation.
- Parkinson’s disease. There is even some evidence that Sildenafil may have properties that help brain functions (attention, memory).
Sildenafil may also help restore erectile dysfunction in some men who have had the following conditions or treatments:
- Spina bifida, a congenital defect of the spinal cord.
- Spinal cord injury with some erectile response.
- Radiation therapy for local prostate cancer. Advanced radiation techniques, such as 3D conformal therapy, along with sildenafil offer the best chances for success (70% in one study).
- Nerve-sparing radical prostatectomy. Sildenafil restores potency in an average of 30% of patients who have had this surgery for prostate cancer. It may be considerable more effective in younger men who were potent before surgery and who had bilateral nerve-sparing procedures. It is unlikely to be effective for men over 55 who had unilateral or non-nerve-sparing procedures. When it works, it may take nine months or longer, so men might benefit from alprostadil injections starting right after surgery. They help prevent scarring and preserve elasticity.
Higher-Risk Candidates. Men with the following conditions should not take sildenafil without the recommendation of their physicians and even then should use it with caution:
- Severe heart disease, such as unstable angina, a history of heart attack, or arryhthmias. Sildenafil increases nerve activity associated with cardiovascular function, especially during physical and mental stress. Men with heart disease may benefit from an exercise test to determine whether resuming sexual activity increases their risk of a heart attack. [See also Effects on the Heart, below.]
- Recent history of stroke.
- Hypotension (very low blood pressure).
- Uncontrolled diabetes.
- Uncontrolled hypertension.
- Taking anticoagulant therapy.
- Heart failure.
Retinitis pigmentosa. (With this genetic disease, people do not produce phosphodiesterase-5 and do not respond to sildenafil.)
Administration and Effect. Sildenafil is effective within 20 to 40 minutes; its effects may last for several hours. The drug works only when the man experiences some sexual arousal. Patients usually take 50 mg, although lower doses (e.g., 25 mg) may be appropriate in some groups, such as elderly patients. Sildenafil should not be used more than once a day and the dose should not exceed 100 mg. It may help men who did not respond to initial therapy with penile injections. and can also be used together with injections, though side effects can be quite intense when the combination is used.
Side Effects and Other Limitations. Common side effects include flushing, gastrointestinal distress, headache, nasal congestion, and dizziness.
Effects on the Heart. There were early reports of fatal heart attacks in a small percentage of men taking the drug. While more recent studies are not finding a higher risk for heart attack so far in men who take Viagara, its effects on the heart and circulation are mixed. On the one hand, a small 2001 study reported that it may improve blood flow to the heart. However, another 2001 study reported that the drug may excite the nerves associated with heart function. And it is known to cause small drops in blood pressure. Of specific concern in this regard are sudden and possibly dangerous drops in blood pressure when Viagara is taken with nitrates, such as nitroglycerine, which are used for angina. The effects have been fatal in some men. No one taking nitrates, including the recreational drug amyl nitrate, should take sildenafil. The bottom line is that caution is still warranted for men with severe heart disease until more research has been conducted.
Visual Effects. About 2.5% of men experience abnormal visual effects that include seeing a blue haze, temporary increased brightness, and even temporary vision loss in a few cases. Experts believe that visual disturbances are related to the inhibition of phosphodiesterase enzymes in the retina, but the effect appears to be temporary and insignificant, lasting a few minutes to several hours. Men at risk for eye problems who take sildenafil regularly should have frequent eye examinations with an ophthalmologist. Men should also see an eye doctor if visual problems last more than a few hours.
Risk of Priapism. The drug poses a very low risk for priapism in most men. (Priapism is sustained, painful, and unwanted erection.) Exceptions are young men with normal erectile function who take sildenafil.
Interactions with Other Drugs. In addition to serious interactions with nitrates, it also may interact with certain antibiotics, such as erythromycin, and acid blockers, such as cimetidine (Tagamet). Patients should tell their physician about any medications they are taking.
Decrease in Effectiveness. Over time, sildenafil may lose effectiveness. A 2001 study found that after two years, 20% of patients had increased their dose to achieve the same effect, and 17% had discontinued sildenafil due to loss of efficacy. It is possible that these men were suffering from heart disease or other problems that was making their impotence worse. An earlier study found that 96% of men who had been taking sildenafil for two to three years remained satisfied with the treatment.
New Generation PDE5 Inhibitors
Researchers are investigating a newer version of drugs that inhibit the enzyme targeted by sildenafil, phosphodiesterase-5 (PDE5).
IC351 (Cialis). Cialis is a potent and highly selective PDE5 inhibitor and may not affect other parts of the body, including the brain, heart, kidney and eyes. Clinical trials are reporting significant success rates in up to 88% of patients. It appears to take effect in 15 minutes and the effects last up to 24 hours. Improved results were reported in men suffering from erectile dysfunction of varying severity and causes. Common side effects include headache, muscle pain, stomach upset following meals, and back pain. Additional trials of the drug are under way.
Vardenafil. Vardenafil is another PDE5 inhibitor currently being investigated. One small study concluded that it increased penile rigidity and tumescence. Another found that it may aid men who have impotence because of prostate cancer surgery. Further evaluation is warranted.
Angiotensin-Receptor Blockers for Men with Hypertension
Recent drugs known as angiotensin-receptor blockers (ARBs), also known as angiotensin II receptor antagonists are being used to lower blood pressure in men with hypertension. In one study after 12 weeks of treatment with an ARB called losartan (Cozaar), 88% of hypertensive males with sexual dysfunction reported improvement in at least one area of sexuality. The number of men reporting impotence declined from 75.3% to 11.8%. Other ARBs include candesartan (Atacand), telmisartan (Micardis), and valsartan (Diovan).
Testosterone Replacement Therapy
Replacement Therapy for Hypogonadism. Testosterone replacement therapy may be effective in inducing puberty in adolescent boys with hypogonadism and may also be helpful for some adult patients with the condition. Some experts believe testosterone replacement therapy also may be helpful for older men whose testosterone levels are deficient. Over the course of about three months, it may gradually heighten sexual interest. It can also improve bone density, boost energy and mood, and increase muscle mass and weight.
Forms of testosterone therapy include the following:
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