Erectile Dysfunction Explained
"The penis does not obey the order of its master, who tries to erect or shrink it at will. The penis must be said to have its own mind, by any stretch of the imagination,’’ once wrote Leonardo da Vinci. Though the first person to discover through an autopsy that the erect penis is full of blood, this versatile Renaissance man also failed to understand how an erection occurs.
Erectile dysfunction (ED) or male impotence is defined as the inability of a man to achieve and maintain an erection sufficient for mutually satisfactory intercourse with his partner. The 1992 National Institutes of Health Consensus Development Conference1 recommends the use of the term "erectile dysfunction" rather than "impotence," because it more accurately defines the problem and has fewer disparaging connotations. An estimated 10 to 20 million American men have some degree of erectile dysfunction.1,2
Cigarette smoking in this study did not show a greater probability of complete erectile dysfunction. However, when it was associated with heart disease and hypertension a greater probability of erectile dysfunction was noted.
A recent survey of 1 000 men in the United Kingdom, aged between 18 and 75, showed that 39% reported experiencing some form of erectile dysfunction. In the United States, an estimated 30 million men suffer from the condition.
Although many women -- and men as well -- continue to view ED as a sexual issue, in truth, the most common causes are undiagnosed physical conditions such as diabetes, high cholesterol, or even the earliest stages of heart disease. Even more often, it can be the result of certain medications used to treat these conditions, particularly some high blood pressure drugs.
Sexual dysfunction is often associated with disorders such as diabetes, high blood pressure, heart disease, nervous system disorders, and depression. Erectile dysfunction may also be an unwanted side effect of medication. In some men, sexual dysfunction may be the symptom of such disorders that brings them to the doctor's office.
The successful treatment of impotence has been demonstrated to improve intimacy and satisfaction, improve sexual aspects of quality of life as well as the overall quality of life, and relieve symptoms of depression.
Although this information focuses primarily on male ED, remember that the partner plays an integral role. If successful and effective management is to occur, any discussion of treatment should include the couple.
For a man to have an erection, a complex process takes place within the body.
An erection involves the central nervous system, peripheral nervous system, psychological and stress-related factors, local problems with the erection bodies or penis itself as well as hormonal and vascular (blood flow or circulation) factors. The penile portion of the process leading to erections represents only a single component of a very complicated and complex process.
Erections occur in response to touch, smell, and visual stimuli that trigger pathways in the brain. Information travels from the brain to the nerve centres at the base of the spine, where primary nerve fibres connect to the penis and regulate blood flow during erection and afterwards.
Sexual stimulation causes the release of chemicals from the nerve endings in the penis that trigger a series of events that ultimately cause muscle relaxation in the erection bodies of the penis. The smooth muscle in the erection body controls the flow of blood into the penis. When the smooth muscle relaxes, the blood flow dramatically increases, and the erection bodies become full and rigid, resulting in an erection. Venous drainage channels are compressed and close off as the erection bodies enlarge.
Detumescence (when the penis is no longer in a state of erection) results when muscle-relaxing chemicals are no longer released. Ejaculation causes the smooth muscle tissue of the erection bodies in the penis to regain muscle tone, which allows the venous drainage channels to open and the blood drains from the penis.
Other male problems, such as premature ejaculation and loss of libido (decreased sexual desire), are also very common. The NHSLS found that 28.5% of men aged 18-59 years reported premature ejaculation, and 15.8% lacked interest during the past year. An additional 17% reported anxiety about sexual performance, and 8.1% indicated a lack of pleasure from sexual activity.
Impotence/Erectile Dysfunction Causes
Erectile dysfunction can be caused by any number of physical and psychological factors. In general, ED is divided into organic (having to do with a bodily organ or organ system) and psychogenic (mental) impotence, but most men with organic causes have a mental or psychological component as well.
Erection problems will usually produce a significant psychological and emotional reaction in most men. This is often described as a pattern of anxiety and stress that can further interfere with normal sexual function. This "performance anxiety" needs to be recognized and addressed by your doctor.
Almost any disease can affect erectile function by altering the nervous, vascular, or hormonal systems. Various diseases may produce changes in the smooth muscle tissue of the penis or influence mood and behaviour.
Vascular diseases account for nearly half of all cases of ED in men older than 50 years. Vascular disease includes atherosclerosis (fatty deposits on the walls of arteries, also called hardening of the arteries), a history of heart attacks, peripheral vascular disease (problems with blood circulation), and high blood pressure. Prolonged tobacco use (smoking) is considered an important risk factor for ED because it is associated with poor circulation and reduced blood flow in the penis.
Trauma to the pelvic blood vessels and nerves is another potential factor in the development of ED. Bicycle riding for long periods has been implicated, so some of the newer bicycle seats have been designed to soften pressure on the perineum (the soft area between the anus and the scrotum).
- Medications used to treat other medical disorders may cause ED.
- Systemic diseases associated with ED
- Diabetes
- Scleroderma
- Renal (kidney) failure
- Liver cirrhosis
- Hemochromatosis (too much iron in the blood)
- Cancer and cancer treatment
- Diseases of the nervous system associated with ED
- Epilepsy
- Stroke
- Multiple sclerosis
- Guillain-Barré syndrome
- Alz
- heimer disease Trauma
- Parkinson disease
- Respiratory disease associated with ED: Chronic obstructive pulmonary disease
- Endocrine conditions associated with ED
- Hyperthyroidism
- Hypothyroidism
- Hypogonadism
- Penile conditions associated with ED
- Peyronie disease
- Priapism (painful, abnormally prolonged erections)
- Mental conditions associated with ED
- Depression
- Widower syndrome
- Performance anxiety
- Nutritional states associated with ED
- Malnutrition
- Zinc deficiency
- Blood diseases associated with ED
- Sickle cell anemia
- Leukemias
- Surgical procedures associated with ED
- Procedures on the brain and spinal cord
- Retroperitoneal or pelvic lymph node dissection
- Aortoiliac or aortofemoral bypass
- Abdominal perineal resection
- Proctocolectomy
- Radical prostatectomy
- Transurethral resection of the prostate
- Cryosurgery of the prostate
- Cystectomy
- Common medications associated with ED
- Antidepressants
- Antipsychotics
- Antihypertensives (for high blood pressure)
- Antiulcer drugs such as cimetidine (Tagamet)
- Hormonal medication such as Zoladex, Lupron, finasteride (Proscar), or dutasteride (Avodart)
- Drugs that lower cholesterol
- Alcohol abuse
- Mind-altering agents such as marijuana and cocaine
Erectile Dysfunction Treatment
Psychologic Treatment
The couple should be emotionally compatible. Both partners should be willing to participate and cooperate with therapy. Major relationship problems should be addressed before therapy is introduced. Similarly, major stresses with work, finances, or family will need to be evaluated and corrected first. Performance anxiety, specifically related to fear of sexual failure, is best evaluated and treated by a qualified sex therapist (psychologist or psychiatrist). At times, minor relationship problems manifest after organic causes of sexual dysfunction have been corrected. These minor problems may be caused by fear of failure, fear of frustration, or embarrassment.
Decreased libido may be psychologic in origin and may necessitate sexual therapy and possibly pharmacologic treatment. Ejaculation problems can be either organic or psychological, and the sex therapist will help patients with premature ejaculation as well as with problems involving anejaculation or retarded ejaculation.
Medical Treatment
If organic problems seem to be dominant, the first step is to identify the medical risk factors and correct them, if possible. Plasma glucose must be regulated in men with poorly controlled diabetes. Medications for hypertension must be optimized. Cessation of tobacco abuse is important. Hyperlipidemia must be treated aggressively. Intake of alcohol should be decreased or discontinued. The use of illicit drugs must be discontinued. Anticipated improvement in sexual function can be a motivational tool to increase patient compliance in the treatment of chronic disease.
Hormonal Treatment
Benign prostatic hyperplasia, prostate cancer, sleep apnea, and polycythemia must be evaluated before and after initiation of testosterone therapy for hypogonadal men. A baseline digital rectal examination of the prostate, a prostate-specific antigen level, and hematocrit should be determined before treatment; if any prostate-related abnormalities are detected, the patient should be referred to a urologist for further evaluation. Any patient treated with replacement androgens should be reassessed within 1 to 3 months after initiation of therapy and then at 6- to 12-month intervals to ensure that clinical problems have not developed or worsened during such treatment.
Testosterone replacement for hypogonadism may also correct sexual dysfunction unless the patient has other comorbid illnesses. For decades, the standard has been a depot intramuscular injection of testosterone enanthate or cypionate every 2 or 3 weeks (200 mg or 300 mg, respectively). Smaller doses and more frequent injections, however, are better at maintaining circulating testosterone lev- else in the normal range (that is, 50 to 150 mg of testosterone enanthate or cypionate intramuscularly at 7- to 14-day intervals). An alternative approach is to administer 100 mg on days 1, 11, and 21 of each month, while allow- ing some flexibility of injection days. If testosterone lev- els are measured, they should be in the normal range just before the next injection.
Other forms of intramuscular testosterone preparations are also being evaluated. Implantable testosterone pellets, which are used in other countries, are now available in the United States, but they are infrequently prescribed. Currently, available tablets for oral administration have generally not been used because of potential liver toxicity. A newer oral capsule, testosterone undecanoate, has been used for more than a decade in Europe but has not yet been approved for use in the United States. Although the safety is not questioned, multiple daily doses are required, and the absorption is erratic. Other orally and sublingually administered testosterone tablets are being evaluated.
Testosterone scrotal and nonscrotal dermal patches have now been approved by the US Food and Drug Administration (FDA). Testosterone absorption is greater through scrotal skin. The scrotal patch was the first to be introduced. These patches are placed on the scrotal skin and are changed daily, in the morning. For many patients, weekly shaving of the scrotum is necessary. The patch increases testosterone levels to the low-normal range, with peak levels achieved 3 to 5 hours after application of the patch. Because 5?-reductase in scrotal skin is high, the dihydrotestosterone (DHT) level in serum becomes quite high. The role of DHT is currently being investigated. The nonscrotal patch (Androderm), applied daily in the evening, may be worn at various sites on the skin.
The hypothalamic-pituitary-gonadal axis has been shown to decrease functioning temporarily after acute medical events or surgical procedures; such an occurrence can cause low gonadotropin and testosterone levels. Similarly, a temporary decrease in testosterone levels may occur as a result of less serious circumstances, such as anxiety, excessive intake of alcohol, use of multiple medications, or uncontrolled diabetes. Patients with these causes are less likely to respond to testosterone replacement. Stimulation of gonadotropins with clomiphene citrate and the subsequent increase in testosterone levels emphasize the functional and reversible nature of this phenomenon; short-term therapy with clomiphene citrate may help some patients. If the testicles are intact, testosterone can be stimulated by injections of human chorionic gonadotropin, but this technique is cumbersome and rarely used. Low testosterone levels can also be caused by suppressed gonadotropins attributable to an increased prolactin level. This situation can be reversed by treatment with bromocriptine, pergolide, or cabergoline. If an increased prolactin level is due to use of a psychotropic drug, however, discontinuing the medication may be all that is needed.
Treatment of other endocrine disorders, such as hypothyroidism or hyperthyroidism, reverses the decreased libido or erectile dysfunction that can accompany these conditions. Uncontrolled diabetes mellitus may respond to improved plasma glucose control, especially in patients with recently diagnosed diabetes. Even patients who have had diabetes for more than 10 years may respond to better glycemic control if a major neuropathy is absent. Hypogonadism is common in patients with diabetes, many of whom may respond to testosterone treatment.
Nonspecific Therapies for Erectile Dysfunction
Some patients do not respond to the aforementioned corrective measures and wish to try nonspecific therapy for erectile dysfunction. This scenario might especially exist in older men and those with numerous medical risk factors. The major options to consider at the present time are yohimbine tablets, vacuum pump devices, venous constriction rings, corpora cavernosal injections of various chemicals, intraurethral drug suppositories, intrapenile arterial or venous surgical procedures, penile implants, or orally administered phosphodiesterase inhibitors. Trials with sublingually administered apomorphine and vasodilators are ongoing.
Sildenafil has recently been approved by the FDA. It inhibits phosphodiesterase type 5, which predominates in the penile tissue (Fig. 2). This action prevents the break- down of cyclic guanosine monophosphate, which, therefore, increases smooth muscle relaxation in the corpora cavernosa and enhances penile rigidity. Three doses are available—25 mg, 50 mg, and 100 mg. If the patient does not have hypogonadism and has no contraindications to the use of this drug, a clinical trial with sildenafil is indicated. Treatment is usually initiated with the 50-mg tablet, which is then decreased to 25 mg if major side effects are noted or increased to 100 mg if there is a lack of efficacy. The tablet is taken 1 hour before sexual activity, and sexual stimulation is necessary. Sildenafil is contraindicated in patients taking nitrates in any form, inasmuch as severe hypotension and resultant syncope have occurred. Side effects are generally mild and tolerable: headaches, hot flashes, heartburn, diarrhea, myalgias, hypotension, and dizziness. The drug may inhibit phosphodiesterase type 6 in the eye, with resultant difficulty in discriminating blue from green, bluish tones in vision, or difficulty seeing in dim light. Whether any adverse effect occurs in diabetic retinopathy or other eye diseases is yet to be determined.
Yohimbine, a derivative of the African Yohimbe tree, has been available for several decades. This is effective in some cases of psychologic or organic erectile dysfunction, but its efficacy is controversial. A tablet is available in one strength, 5.4 mg (1/12 gr), and the standard dosage is one tablet three times a day. If the patient has a response, it will generally occur within the first 4 weeks. A short course of two tablets three times a Male Sexual Dysfunction may be taken.
The Most Commonly Used Nonspecific Treatments for Erectile Dysfunction
- Yohimbine tablets
- Venous constriction rings
- Vacuum devices
- Pharmacologic erection program
- Intracavernosal injections
- Papaverine-phentolamine
- Papaverine-phentolamine-prostaglandin E
- Prostaglandin E
- Potassium channel openers
- Intraurethral suppositories
- Prostaglandin E
- Penile microvascular arterial bypass operation
- Penile venous ligation surgical procedure
- Penile implants
- Flexible rods
- Inflatable cylinders
Orally administered phosphodiesterase inhibitors such as
- Viagra
- Cialis
- Levitra
Treatment directed to the skin of the penile shaft has been attempted. Nitroglycerin paste increased penile rigidity but rarely enough to allow penetrability. Furthermore, absorption into the female partner often caused headaches. The use of a nitroglycerin patch decreased this side effect but did not enhance the therapeutic response. Topically applied minoxidil, alone or in combination with a transdermal enhancing compound, did not improve erections enough to warrant its general use. Various topical preparations of PGE1 are being studied in clinical trials.
Diabetes and Erectile Dysfunction
Most people with diabetes know the long-term effects it can have on the body. That's why they strive to live a healthy lifestyle and monitor their condition. If you're a man with diabetes, you have an increased chance of erectile dysfunction (ED), which doctors call a "risk factor" from diabetes. Men with type 1 diabetes have a greater risk of ED than men with type 2 diabetes.
It is thought that at least 50% of diabetic men have erectile dysfunction. Erectile dysfunction occurs at a younger age in diabetic men and usually occurs within 10 years of diagnosis of the disease. It also is well known that not all diabetics develop erectile dysfunction, but those individuals with certain associated diabetic-related complications such as peripheral neuropathy have a very high association of erectile dysfunction. On the other hand, prostate problems can also occur in diabetics. Our goal is, in this communication, to update you on the current management of diabetic erectile dysfunction in light of the introduction of Sildenafil.
If you have ED or some other sexual problem, it’s normal to feel embarrassed or upset. You may blame yourself or your partner. Some men feel guilty and angry. Others feel like there’s no hope. These feelings can make it hard to talk openly with your partner or your doctor. But talking about ED means you’re a step closer to getting help.
The normal male sexual function requires a complex interaction of vascular, neurological, hormonal, and psychological systems. The initial obligatory event is the acquisition and maintenance of an erect penis, which is a vascular phenomenon. Normal erections require blood flow into the corpora cavernous and corpus spongiosum. As the blood accelerates, the pressure within the intracavernosal space increases dramatically to choke off penile venous outflow. This combination of increased intracavernosal blood flow and reduced venous outflow allows a man to acquire and maintain a firm erection.
Nitric oxide also plays a significant role. High levels of nitric oxide act as local neurotransmitters and facilitate the relaxation of intracavernosal trabeculae, thereby maximizing blood flow and penile engorgement. Loss of erection, or detumescence, occurs when nitric oxide-induced vasodilation ceases.
Low intracavernosal nitric oxide synthase levels are found in people with diabetes, smokers, and men with testosterone deficiency. Interference with oxygen delivery or nitric oxide synthesis can prevent intracavernosal blood pressure from rising to a level sufficient to impede emissary vein outflow, leading to an inability to acquire or sustain a rigid erection. Examples include decreased blood flow and inadequate intracavernosal oxygen levels when atherosclerosis involves the hypogastric artery or other feeder vessels and conditions, such as diabetes, that are associated with suboptimal nitric oxide synthase activity.
Erections also require neural input to redirect blood flow into the corpora cavernosal. Psychogenic erections secondary to sexual images or auditory stimuli relay sensual input to the spinal cord at T-11 to L-2. Neural impulses flow to the pelvic vascular bed, redirecting blood flow into the corpora cavernosal. Reflex erections secondary to tactile stimulus to the penis or genital area activate a reflex arc with sacral roots at S2 to S4. Nocturnal erections occur during rapid-eye-movement (REM) sleep and occur 3-4 times nightly. Depressed men rarely experience REM sleep and therefore do not have nocturnal or early-morning erections.
In addition to medication, your doctor may recommend the following.
Controlling Blood Sugar
This may help prevent and reduce nerve and blood vessel problems. Some of the things your doctor recommends may be part of your diabetes program already. Be sure to discuss any new recommendations with all of your doctors and healthcare professionals, as some new advice may conflict with your current program.
Be "Heart Healthy"
Since heart disease and high blood pressure can contribute to ED if you have diabetes, you should do what you can to keep your heart healthy and control your blood pressure. This may include changes in diet and exercise. Be sure to discuss any diet or exercise program with your doctor before starting it. If you have a cardiovascular condition already, you should continue to work with your doctor to make sure both conditions are treated together safely.
Avoid Large Amounts of Alcohol
Drinking large amounts of alcohol can make achieving an erection more difficult. Usually, men should have two or fewer drinks per day.
Quit or Reduce Tobacco Intake
Tobacco products can cause arteries to narrow and become blocked over time, which can also lessen the blood flow needed to achieve an erection.
Counselling
Depression, anxiety and stress can all contribute to ED, whether caused by diabetes or not. Counselling can alleviate these feelings, and help restore a more positive, confident attitude.
The information contained here is provided by a third-party publication as a courtesy to our visitors. It is not to be considered an endorsement by Lilly ICOS LLC. Remember, only your doctor or other healthcare professional can determine if you have erectile dysfunction and if treatment is right for you.