Constriction of the trabecular smooth muscle and helicine arteries induced by sympathetic innervation makes the penis flaccid, with blood pressure in the cavernosal sinuses of the penis near venous pressure. Acetylcholine is thought to decrease sympathetic tone. This may be important in a permissive sense for adequate trabecular smooth muscle relaxation and consequent effective action of other mediators in achieving sufficient inflow of blood into the lacunar spaces. When the trabecular smooth muscle relaxes and helicine arteries dilate in response to parasympathetic stimulation and decreased sympathetic tone, increased blood flow fills the cavernous spaces, increasing the pressure within these spaces so that the penis becomes erect. As the venules are compressed against the tunica albuginea, penile pressure approaches arterial pressure, causing rigidity. Once this state is achieved, arterial inflow is reduced to a level that matches venous outflow.
In some cases, nocturnal penile tumescence testing is performed to find out whether the man has erections while asleep. Healthy men usually have about four or five erections throughout the night. The man applies a device to the penis called a Rigiscan before going to bed at night, and the device can determine whether he has had erections. (If a man is able to have normal erections at night, this suggests a psychological cause for his impotence.)
Tadalafil (Cialis) is the third oral medicine approved by the U.S. FDA for the treatment of erectile dysfunction. Like sildenafil (Viagra) and vardenafil (Levitra), tadalafil inhibits PDE5 (as described earlier). Unlike the other PDE 5 inhibitors, patients should take tadalafil once daily and is approved for the treatment of BPH (benign enlargement of the prostate).
Erectile dysfunction (previously called impotence) is the inability to get or maintain an erection that is sufficient to ensure satisfactory sex for both partners. This problem can cause significant distress for couples. Fortunately more and more men of all ages are seeking help, and treatment for ED has advanced rapidly. The enormous demand for “anti-impotence” drugs suggests that erection problems may be more common than was previously thought. Find out more about the causes and treatment of erectile dysfunction here.

Is your erectile dysfunction due to psychological (stress, relationship problems, etc.) or physical factors? Your doctor may ask if you note erections at night or in the early morning. 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. Men with psychogenic erectile dysfunction may relate the onset of problems to a "stressor," such as failed relationship. Your doctor may suggest a test to determine if you have erections during sleep, which may suggest that there may be a psychological cause of the erectile dysfunction.


There are many effective treatments for impotence. The most popular is a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. These include sildenafil (Viagra), vardenafil (Levitra), tadalafil (Cialis) and avanafil (STENDRA). These drugs are taken in pill form. They work in most men. But they are less effective in men with neurological causes of impotence.

Three forms of penile prostheses are available for patients who fail with or refuse other forms of therapy: semirigid, malleable, and inflatable. The effectiveness, complications, and acceptability vary among the three types of prostheses, with the main problems being mechanical failure, infection, and erosions. Silicone particle shedding has been reported, including migration to regional lymph nodes; however, no clinically identifiable problems have been reported as a result of the silicone particles. There is a risk of the need for reoperation with all devices. Although the inflatable prostheses may yield a more physiologically natural appearance, they have had a higher rate of failure requiring reoperation. Men with diabetes mellitus, spinal cord injuries, or urinary tract infections have an increased risk of prosthesis-associated infection. This form of treatment may not be appropriate in patients with severe penile corporal fibrosis, or severe medical illness. Circumcision may be required for patients with phimosis and balanitis.
Circulatory problems: An erection occurs when the penis fills with blood and a valve at the base of the penis traps it. Diabetes, high blood pressure, cholesterol, clots, and atherosclerosis (hardening of the arteries) can all interfere with this process. Such circulatory problems are the number one cause of erectile dysfunction. Frequently, erectile dysfunction is the first noticeable symptom of cardiovascular disease.
Exercise and lifestyle modifications may improve erectile function. Weight loss may help by decreasing inflammation, increasing testosterone, and improving self-esteem. Patients should be educated to increase activity, reduce weight, and stop smoking, as these efforts can improve or restore erectile function in men without comorbidities. Precise glycemic control in diabetic patients and pharmacologic treatment of hypertension may be important in preventing or reducing sexual dysfunction. [49]

Conditions that may be associated with ED include diabetes, [25, 26, 27] hypertension, [28] , and CAD, as well as neurologic disorders, endocrinopathies, benign prostatic hyperplasia, [29] , sleep apnea [30] , COPD, [31] and depression (see Table 1 below). [32, 33, 34, 35] In fact, almost any disease may affect erectile function by altering the nervous, vascular, or hormonal systems. Various diseases may produce changes in the smooth muscle tissue of the corpora cavernosa or influence the patient’s psychological mood and behavior.


#2 Physically exhausted. If you’ve been cranking it at the gym, haven’t been sleeping well, or you’ve been working your ass off at your job, getting tangled up with your lover for even more physically demanding activities may not sound ideal. Physical exhaustion has a direct effect on your ability to get aroused. The only fix for this one is to get some rest.
So what can you do to help things along a little?  Well, chances are it may sort itself out as you settle in to your relationship. But if it keeps happening and you see a future in the relationship, you need to talk about it, or it will soon become the elephant in the bedroom. Pick a time with no distractions and where nobody can overhear you. Tell them that you care about them and that you don’t need to rush things sexually. This can take the pressure off the need to perform. 
In comparison, 37% of men who had received external radiotherapy as their primary therapy reported the ability to attain functional erections suitable for intercourse, along with 43% of men who had received brachytherapy as primary treatment. Pretreatment sexual health-related quality of life score, age, serum prostate-specific antigen (PSA) level, race or ethnicity, body mass index, and intended treatment details were associated with functional erections 2 years after treatment. [45]

Infection is a concern after placement of a prosthesis and is a reported complication in 8%-20% of men undergoing placement of a penile prosthesis. If a prosthesis becomes infected (redness, pain, and swelling of the penis and sometimes purulent drainage are signs of infection), the prosthesis must be removed. Depending on the timing and severity of the infection and your surgeon's preference, the area can be irrigated extensively with antibiotic solutions and a new prosthesis placed at the same time or removal of the infected prosthesis and an attempt to place a new prosthesis made at a later time when the infection is totally cleared.
It is normal for a man to have five to six erections during sleep, especially during rapid eye movement (REM). Their absence may indicate a problem with nerve function or blood supply in the penis. There are two methods for measuring changes in penile rigidity and circumference during nocturnal erection: snap gauge and strain gauge. A significant proportion of men who have no sexual dysfunction nonetheless do not have regular nocturnal erections.

Monitoring erections that occur during sleep (nocturnal penile tumescence) can help you and your doctor to understand if the erectile dysfunction is due to psychological or physical causes. The nocturnal penile tumescence test is a study to evaluate erections at night. Normally men have three to five erections per eight hours of sleep. The test can be performed at home or in a sleep lab. The most accurate way to perform the test involves a special device that is connected to two rings. The rings are placed around the penis, one at the tip of the penis and the other at the bottom (base) of the penis. The device records how many erections occur, how long they last, and how rigid they are. The test is limited in that it does not assess the ability to penetrate.
Penile prostheses are very effective, and most patients who have a prosthesis placed are satisfied with the prosthesis. However, placement of a prosthesis causes scarring of the tissue within the corpora cavernosa, and if the prosthesis requires removal, other forms of therapy, except for the vacuum device, are often not effective. Thus, most physicians reserve placement of a prosthesis for men who have tried and failed or have contraindications to other therapies.
However, a review of a United Kingdom medical record database found no evidence that the use of 5-alpha reductase inhibitors independently increase the risk for ED. In 71,849 men with benign prostatic hyperplasia (BPH), the risk of ED was not increased with the use of finasteride or dutasteride only (odds ratio [OR] 0.94), or a 5-alpha reductase inhibitor plus an alpha blocker (OR 0.92) compared with an alpha blocker only. In addition, the risk of ED was not increase in 12 346 men prescribed finasteride 1 mg for alopecia, compared with unexposed men with alopecia (OR 0.95). The risk of ED did increase with longer duration of BPH, regardless of drug exposure. [48]
Diabetes mellitus: Erectile dysfunction tends to develop 10 to 15 years earlier in diabetic men than among nondiabetic men. The increased risk of erectile dysfunction among men with diabetes mellitus may be due to the earlier onset and greater severity of atherosclerosis (hardening of the arteries) that narrows the arteries and thereby reduces the delivery of blood to the penis. Atherosclerosis can affect the arteries in the penis, as well as the arteries in the pelvis that supply the penile arteries. Diabetes mellitus also causes erectile dysfunction by damaging nerves that go to the penis, much like the effect of diabetes on nerves in other areas of the body (diabetic neuropathy). Diabetes can also affect the muscles in the penis, leading to troubles with erections. 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 people with diabetes.

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. Doctors may check thyroid levels in some individuals as both hypothyroidism (low thyroid function) and hyperthyroidism (overactive thyroid function) can contribute to erectile dysfunction.

Little is known about the natural history of erectile dysfunction. This includes information on the age of onset, incidence rates stratified by age, progression of the condition, and frequency of spontaneous recovery. There also are very limited data on associated morbidity and functional impairment. To date, the data are predominantly available for whites, with other racial and ethnic populations represented only in smaller numbers that do not permit analysis of these issues as a function of race or ethnicity.
You should talk to your doctor about possible treatments. You may want to talk to other patients who have had the treatment planned for you. You also may want to seek a second doctor's opinion about surgery before making your decision. You may find it difficult to talk to your doctor about impotence. You will want to find a doctor who treats this condition and will help you feel comfortable talking about the problem and choosing the best treatment. You can also get more information by contacting your local National Kidney Foundation affiliate.
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 (such as sildenafil). In some cases, treatment can involve prostaglandin tablets in the urethra, injections into the penis, a penile prosthesis, a penis pump or vascular reconstructive surgery.[1]
Alprostadil should not be used in men with urethral stricture (scarring and narrowing of the tube that urine and the ejaculate pass through), balanitis (inflammation/infection of the glans [tip] of the penis, severe hypospadias (a condition where the opening of the urethra is not at the tip of the penis, rather on the underside of the penis), penile curvature (abnormal bend to the penis), and urethritis (inflammation/infection of the urethra).
In men, erectile dysfunction can be defined as being a persistent inability to get or keep an erection that is firm enough to attain sexual satisfaction. It should not be confused with the occasional incident when this occurs, which is an experience common to the vast majority of men for various reasons. These can include having had too much alcohol to drink, being overly-anxious about a new sexual partner, or being worried about current events in your life. The issue would only be classed as Erectile Dysfunction if it keeps happening again and again. Again, an erection once attained should be hard enough and last long enough to be satisfactory. Other conditions, like premature ejaculation, may interfere in this process but these are different problems, and would be treated differently.
This statement is more than five years old and is provided solely for historical purposes. Due to the cumulative nature of medical research, new knowledge has inevitably accumulated in this subject area in the time since the statement was initially prepared. Thus some of the material is likely to be out of date, and at worst simply wrong. For reliable, current information on this and other health topics, we recommend consulting the National Institutes of Health's MedlinePlus http://www.nlm.nih.gov/medlineplus/.

A common and important cause of ED is vasculogenic. Many men with ED have comorbid conditions such as hyperlipidemia, hypercholesterolemia, tobacco abuse, diabetes mellitus, or coronary artery disease (CAD). [6] The Princeton III Consensus recommends screening men who present with ED for cardiovascular risk factors; ED may be the earliest presentation of atherosclerosis and vascular disease. [7]


The term "impotence," as applied to the title of this conference, has traditionally been used to signify the inability of the male to attain and maintain erection of the penis sufficient to permit satisfactory sexual intercourse. However, this use has often led to confusing and uninterpretable results in both clinical and basic science investigations. This, together with its pejorative implications, suggests that the more precise term "erectile dysfunction" be used instead to signify an inability of the male to achieve an erect penis as part of the overall multifaceted process of male sexual function.

The pathogenesis of organic ED is related to dysfunction of the endothelium. Endothelial cells can become injured through a variety of mechanisms, most of which cause oxidative stress on the tissues. Many of these causes of oxidative stress are related to lifestyle issues which lead to hypertension, diabetes and dyslipidaemia (figure 1). Endothelial cell dysfunction results in reduction of endothelium-dependent vasorelaxation as well as increased adhesion of leukocytes to the endothelium. Endothelial cell injury then leads to a variety of sequelae, including ED, other types of vasoconstriction, atherosclerosis and thrombus formation.18
In a prospective study from the Prostate Cancer Prevention Trial database, Thompson et al reported that men presenting with ED had a significantly higher chance of developing a cardiovascular event over a 7-year follow-up period. [55] The hazard ratio was 1.45, which is in the range of risk associated with current smoking or a family history of MI.
Anxiety is particularly pernicious. It triggers the fight-or-flight reflex that sends blood away from the central body, including the penis, and out to the limbs for self-defense or escape. Less blood in the central body means less blood available for erection. Erection dissatisfaction is upsetting, but try to accept it. It’s normal. And when men become anxious about it, erections become less likely.
If you can keep an erection when you’re alone, then you’re probably worried about something when you’re with your partner. Think about how you feel and then talk to your partner about your concerns. You might be putting too much pressure on yourself or not protecting yourself by using condoms and birth control. Or maybe you’ll discover that you’re really not ready for sex right now and need to wait until it feels right.
So not only are erectile problems common, they're nothing for you or your special friend to be freaked out about. Check out the nine most common reasons that dudes sometimes can't get it up, and get ready to become the soothing voice of reason the next time the guy you're with has a hard time pitching his tent in your happy valley. Everything (and every penis) is gonna be fine!
One thing you need to know.  When you are experiencing anxiety, you get a stress response.  You can read more about this here.  A stress response is what you automatically feel, say, if a fight broke out near you.  Your body gets ready to protect itself.  During a stress response, blood is diverted away from less important areas to help your heart beat faster.
In comparison, 37% of men who had received external radiotherapy as their primary therapy reported the ability to attain functional erections suitable for intercourse, along with 43% of men who had received brachytherapy as primary treatment. Pretreatment sexual health-related quality of life score, age, serum prostate-specific antigen (PSA) level, race or ethnicity, body mass index, and intended treatment details were associated with functional erections 2 years after treatment. [45]
The Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) study, designed to determine whether an individual man’s sexual outcomes after most common treatments for early-stage prostate cancer could be accurately predicted on the basis of baseline characteristics and treatment plans, found that 2 years after treatment, 177 (35%) of 511 men who underwent prostatectomy reported the ability to attain functional erections suitable for intercourse. [45]
Erectile dysfunction can have so many long-lasting effects that the inability to achieve an erection is almost the least of them. Men who suffer from erectile dysfunction often suffer from self-esteem concerns, and these can then translate into issues regarding sexual relationships, friendships, and even work-related relationships. As things begin to spiral out of control, men dealing with erectile dysfunction may go on to suffer from depression, anxiety, and other psychological problems that further inhibit relationship and sexual intimacy. So what is it that’s causing this mess?

Following a detailed discussion about the history of erectile dysfunction and its risk factors, your doctor will examine the testicles and penis to help determine the cause of erectile dysfunction. Your doctor will check reflexes and pulses in the area to see if problems with blood vessels or nerves are contributing to the erectile dysfunction. If necessary, your doctor will order tests to help diagnose erectile dysfunction.
Sexual dysfunction and ED become more common as men age. The percentage of complete ED increases from 5% to 15% as age increases from 40 to 70 years. But this does not mean growing older is the end of your sex life. ED can be treated at any age. Also, ED may be more common in Hispanic men and in those with a history of diabetes, obesity, smoking, and hypertension. Research shows that African-American men sought medical care for ED twice the rate of other racial groups.
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