The role of the endothelium in ED has been noted for a number of years and the overlapping of ED and other conditions, especially coronary heart disease, CVD, affecting endothelial function/dysfunction, is clearly present. The endothelial cell is now known to affect vascular tone and impact the process of atherosclerosis, and impacting ED, CVD and peripheral vascular disease.16
The inability to achieve or sustain a sufficiently firm penile erection (tumescence) to allow normal vaginal sexual intercourse. The great majority of cases are not caused by organic disease and most men experience occasional periods of impotence. It is often related to anxiety about performance and is usually readily corrected by simple counselling methods which prescribe sensual massage but forbid coitus. Organic impotence may be caused by DIABETES, MULTIPLE SCLEROSIS, spinal cord disorders and heart disease. Many cases can be helped by the drug SILDENAFIL (Viagra).
Oral phosphodiesterase type 5 inhibitors (PDE5 inhibitors) unless contraindicated are the recommended first line medical therapy for erectile dysfunction. Currently, there are four different PDE5 inhibitors available. They all work the same way and have essentially the same results. They differ in how long they last in your body and in side effects.
The availability of phosphodiesterase-5 (PDE5) inhibitors—sildenafil, vardenafil, tadalafil, and avanafil—has fundamentally altered the medical management of ED. In addition, direct-to-consumer marketing of these agents over the last 15 years has increased the general public’s awareness of ED as a medical condition with underlying causes and effective treatments.
Think of erectile dysfunction as your body’s “check engine light.” The blood vessels in the penis are smaller than other parts of the body, so underlying conditions like blocked arteries, heart disease, or high blood pressure usually show up as ED before something more serious like a heart attack or stroke. ED is your body’s way of saying, “Something is wrong.” And the list of things that cause erectile dysfunction can include:
In one study, 9.6% reported ‘occasional’ erectile dysfunction, 8.9% reported erectile dysfunction occurring ‘often’, and 18.6% reported erectile dysfunction occurring ‘all the time’. Of these, only 11.6% had received treatment.In another study, only 14.1% of men reported that they had received treatment, despite experiencing erectile dysfunction for longer than 12 months.
All studies demonstrate a strong association with age, even when data are adjusted for the confounding effects of other risk factors. The independent association with aging suggests that vascular changes in the arteries and sinusoids of the corpora cavernosa, similar to those found elsewhere in the body, are contributing factors. Other risk factors associated with aging include depression, sleep apnea, and low HDL levels.
Erectile dysfunction can occur as a side effect of medication taken for another health condition. Common culprits are high blood pressure meds, antidepressants, some diuretics, beta-blockers, heart medication, cholesterol meds, antipsychotic drugs, hormone drugs, corticosteroids, chemotherapy, and medication for male pattern baldness, among others.
The most common treatment for erectile dysfunction is drugs known as phosphodiesterase-5 (PDE-5) inhibitors. These include tadalafil (Cialis), vardenafil (Levitra), and sildenafil citrate (Viagra). These are effective for about 75% of men with erectile dysfunction. They are tablets that are taken around an hour before sex, and last between 4 and 36 hours. Sexual stimulation is required before an erection will occur. The PDE-5 inhibitors cause dilation of blood vessels in the penis to allow erection to occur, and help it to stay rigid. Men using nitrate medication (e.g. GTN spray or sublingual tablets for angina) should not use PDE-5 inhibitors.
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Research is mixed on the effectiveness of acupuncture as an erectile dysfunction cure, but one study published in November 2013 in the Journal of Alternative and Complementary Medicine found that acupuncture can be beneficial for men experiencing erectile dysfunction as a side effect of antidepressants, including selective serotonin reuptake inhibitors (SSRIs) and serotonin noradrenaline reuptake inhibitors (SNRIs).

Erosion of the prosthesis, whereby it presses through the corporal tissue into the urethra, may occur. Symptoms and signs may include pain, blood in the urine, discharge, abnormal urine stream, and malfunction. If the prosthesis erodes into the urethra, a physician must remove it. If the other cylinder remains intact, it can be left in place. A physician leaves a catheter in place to allow the urethra to heal.


While erectile dysfunction can occur at any age, the risk of developing erectile dysfunction increases with age. According to the Massachusetts Male Aging Study, the prevalence of erectile dysfunction was 52% in men 40-70 years of age. The prevalence of complete erectile dysfunction increases from 5% at 40 years of age to 15% among men 70 years of age and older.
Causes of impotence are many and include heart disease, high cholesterol, high blood pressure, obesity, metabolic syndrome, Parkinson's disease, Peyronie's disease, substance abuse, sleep disorders, BPH treatments, relationship problems, blood vessel diseases (such as peripheral vascular disease and others), systemic disease, hormonal imbalance, and medications (such as blood pressure and heart medications).
Cavernosography measurement of the vascular pressure in the corpus cavernosum. Saline is infused under pressure into the corpus cavernosum with a butterfly needle, and the flow rate needed to maintain an erection indicates the degree of venous leakage. The leaking veins responsible may be visualized by infusing a mixture of saline and x-ray contrast medium and performing a cavernosogram.[21] In Digital Subtraction Angiography (DSA), the images are acquired digitally.
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]
ED exists in approximately 75% of men with SB and is dependent upon the level of the neurologic lesion (54). The level of the neurologic lesions usually corresponds to sensation and penile sensation indicates pudendal nerve signaling. With absent sacral reflexes ED is variable. Furthermore, Diamond et al. reported that 64% of men with lesions below T10 obtained erections versus 14% with a lesion above T10 (55). It has also been suggested that ED may be underreported due to lack of sexual education even in men without associated cognitive impairment (56).
Because impotence can be due to health problems that can affect the whole body, and because it can interfere with one’s quality of life, it is important to talk with your doctor if you have trouble attaining or maintaining an erection. With increasing discussion of impotence in the media, coupled with advances in treatment, men are now much more comfortable talking with their doctors about impotence. It is currently estimated that between 15 and 30 million men in the United States are affected by impotence (Source: NIDDK).
In later chapters, the book delves into the specific branch of Ayurveda known as Vajikarana. It holds such a powerful imagery in its meaning, “to be like a horse”. Ayurveda sustains balance in the body, mind and consciousness. Nutrition plays an important role and the author offers dietary suggestions and a handful of easily found herbs to complement the program.
Diabetes is an example of an endocrine disease that can cause a person to experience impotence. Diabetes affects the body’s ability to utilize the hormone insulin. One of the side effects associated with chronic diabetes is nerve damage. This affects penis sensations. Other complications associated with diabetes are impaired blood flow and hormone levels. Both of these factors can contribute to impotence.
This technique is effective in 60%-90% of men. It is not recommended to leave the tension ring in place longer than 30 minutes. The vacuum device may be the only therapy that is effective after removal of a penile prosthesis. The vacuum device has become a commonly used therapy as part of penile rehabilitation after radical prostatectomy to preserve the tissue of the penis and prevent scarring within the penis and loss of penile length.

Factors that mediate contraction in the penis include noradrenaline, endothelin-1, neuropeptide Y, prostanoids, angiotensin II, and others not yet identified. Factors that mediate relaxation include acetylcholine, nitric oxide (NO), vasoactive intestinal polypeptide, pituitary adenylyl cyclase–activating peptide, calcitonin gene–related peptide, adrenomedullin, adenosine triphosphate, and adenosine prostanoids.

When sexually stimulated there is a release of a chemical, nitric oxide (NO) in the blood vessels of the corpus cavernosum. The NO stimulates the production of a compound called cGMP, which causes relaxation of the smooth muscle in the blood vessels supplying the corpus cavernosum. PDE 5 is an enzyme that breaks down cGMP. By inhibiting the breakdown of cGMP by PDE5, these medications allow cGMP to build up in the penis. cGMP causes muscles in the corpora cavernosa of the penis to relax. When the muscle is relaxed, more blood can flow into the penis and fill the spaces in the penis. As the penis fills with blood, the veins in the penis are compressed, and this results a hard erection. When the effect on PDE5 decreases, the cGMP levels go down and the muscle in the penis contracts, causing less blood to flow into the penis and allowing the veins to open up and drain blood out of the penis.

It is common for a healthy older man to still want sex and be able to have sex within appropriate limitations. Understanding what is normal in older age is important to avoid frustration and concern. Older men and their partners often value being able to continue sexual activity and there is no age where the man is ‘too old’ to think about getting help with his erection or other sexual problems.


In the Massachusetts Male Aging Study (MMAS) among a community-based survey of men aged 40-70 years, 52% of the men reported some degree of erectile difficulty. Complete ED, defined as the total inability to obtain or maintain suitable erections during sexual stimulation, as well as the absence of nocturnal erections (normal erections [four to six/night], which occur during sleep), occurred in 10% of the men in the study. Lesser degrees of mild and moderate ED occurred in 17% and 25% of participants.
Once implanted, the pumps become “part of their body,” Montague explains. “No out-of-pocket cost per use. Predictable response. Works every time.” Pills, even when they work, might be less effective if you’ve had more than a couple drinks or are out of sorts for other reasons. Injections are slightly more reliable than pills but, Montague says, are still subject to variability.
If PDE5 drugs don't work or cannot be used because of potential side effects, your doctor can recommend other therapies. The drug alprostadil (Caverject, Edex, Muse) allows blood to flow more freely in the penis, leading to an erection. The drug can be injected with a tiny needle into your penis. Or, a small pellet (suppository) can be inserted into the opening of the penis. Suppositories and injections are effective in the majority of men.
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.
Another potential new treatment consists of penile low-intensity shock wave lithotripsy. This consists of 1500 shocks twice a week for 3–6 weeks. The purpose is to stimulate neovascularisation to the corporal bodies with improvement in penile blood flow and endothelial function. The use of low-intensity shock wave lithotripsy may convert PDE5 inhibitor non-responders to responders.47

In one study, 9.6% reported ‘occasional’ erectile dysfunction, 8.9% reported erectile dysfunction occurring ‘often’, and 18.6% reported erectile dysfunction occurring ‘all the time’. Of these, only 11.6% had received treatment.In another study, only 14.1% of men reported that they had received treatment, despite experiencing erectile dysfunction for longer than 12 months.
Cavernosography measurement of the vascular pressure in the corpus cavernosum. Saline is infused under pressure into the corpus cavernosum with a butterfly needle, and the flow rate needed to maintain an erection indicates the degree of venous leakage. The leaking veins responsible may be visualized by infusing a mixture of saline and x-ray contrast medium and performing a cavernosogram.[21] In Digital Subtraction Angiography (DSA), the images are acquired digitally.
In a 2005 study, three months of twice-daily sets of kegel exercises combined with biofeedback and advice on lifestyle changes, such as quitting smoking, losing weight, and limiting alcohol, worked far better than just giving the participants advice. “Wearing tight pants will affect impotence along with some other medical conditions like diabetes and heart disease,” which can also affect a man’s degree of impotence, Dr. Jennifer Burns, specializing in family practice with an emphasis on gastrointestinal health at the BienEtre Center, told Medical Daily.

MUSE should not be used in men with a history of urethral stricture (narrowing of the tube in the penis that urine and semen pass through), inflammation or infection of the glans (tip) of the penis (balanitis), 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).
ED occurs in up to 70% of men with MS, and MS is one of the most prevalent neurological disorders that affect the younger adult population worldwide (33-35). The mean time for SD and ED to develop is about 9 years and is rarely a presenting symptom of MS (36). Men with MS and ED may continue to have nocturnal erections, and psychogenic erections; however, this does not mean they have psychogenic ED but could be an indicator that MS involves the spinal cord (37).
The primary nerve fibers to the penis are from the dorsal nerve of the penis, a branch of the pudendal nerve. The cavernosal nerves are a part of the autonomic nervous system and incorporate both sympathetic and parasympathetic fibers. They travel posterolaterally along the prostate and enter the corpora cavernosa and corpus spongiosum to regulate blood flow during erection and detumescence. The dorsal somatic nerves are also branches of the pudendal nerves. They are primarily responsible for penile sensation. [10]

Alprostadil is a potent vasodilator and smooth muscle relaxant identical to the naturally occurring PGE1. PGE1 binds with specific receptors on smooth muscle cells and activates intracellular adenylate cyclase to produce cAMP, which in turn induces tissue relaxation through a second messenger system (96). PGE1 is the only FDA approved form of intracavernosal therapy and is available commercailly as EDEX, or Caverject. Its efficacy was demonstrated in several clinical trials where the rate of responders ranged from 40% to 80% (97,98). The most common adverse event is penile pain, which is not related to the injection of the medication itself. In men with prolonged use the pain is usually self-limited (99).


The somatosensory pathways for erections originate in the penile skin, glans and urethra. Glans afferent sensory free nerve endings are 10-fold more than their corpuscular receptors, and are derived from Aδ and unmyelinated C fibers. The nerve endings coalesce to form the dorsal penile nerve along with other sensory nerve fibers. Through the pudendal nerve they enter the S2-4 nerve roots to terminate on spinal neurons and interneurons. The dorsal nerve is not purely somatic, however. Nerve bundles within the dorsal nerve contain nitric oxide (NO) synthase, found typically in autonomic nerves, and stimulation of the sympathetic chain can leak to evoked potentials from the dorsal nerve and vice versa (10-12).
What happens is that the blood vessels of the penis are rather small, and a small amount of plaque in the penile arteries is going to result in erectile dysfunction. You need more plaque before the person’s actually symptomatic from a heart problem, but they’re linked. And so when anybody, any man has an erectile issue, it’s incumbent upon the physician to make certain that their cardiac status is healthy.
Effective treatment for erectile dysfunction is available, and for most men will allow the return to a fulfilling sex life. The side effects of the treatment for erectile dysfunction vary depending on the treatment that is used. Some may interrupt the spontaneity of sexual activity. For example, PDE-5 inhibitors typically need to be taken one hour before sex. Side effects may include headaches, indigestion, vasodilation, diarrhoea and blue tinge to vision. Other treatments such as penile injections may cause pain at the injection site, or an erection that will not go down. Treatment options need to be carefully discussed with your doctor to determine which one is best suited to you.
Patients receiving penile prostheses should be instructed in the operation of the prosthesis before surgery and again in the postoperative period. The prosthesis usually is not activated until approximately 6 weeks after surgery, so as to allow the edema and pain to subside. The prosthesis is checked in the office before the patient begins to use it.
Recently, several advances in the uses of stem cells have bet met with great anticipation. Stem cells have the ability to differentiate into different cell lines based on the cellular signaling they receive. Bone marrow mononuclear cells in particular have been used for the treatment of ED in animal models. Yiou et al. recently delivered bone marrow-mononuclear cells (BM-MNC) into the intracavernous smooth muscle of post radical prostatectomy men (123). The open label, dose escalation phase I/II trial showed improvements in IIEF-15 assessment as well as increased vascularization of the corpora based on penile Doppler arterial velocity measurements. Although promising, further investigation in humans is required to substantiate BM-MNCs impact on erections, and erectile function recovery going forward.
While studies are limited, it has been shown that male sexual dysfunction can also negatively impact the sexual function of female partners. A study comparing the sexual function of women with partners with erectile dysfunction to those without showed that sexual arousal, lubrication, orgasm, satisfaction, pain and total score were significantly lower in those who had partners with erectile dysfunction. Later in that study, a large proportion of the men with erectile dysfunction underwent treatment. Following treatment, sexual arousal, lubrication, orgasm, satisfaction and pain were all significantly increased. It was concluded that female sexual function is impacted by male erection status, which may improve following treatment of male sexual dysfunction.
medicines called alpha-blockers such as Hytrin (terazosin
HCl), Flomax (tamsulosin HCl), Cardura (doxazosin
mesylate), Minipress (prazosin HCl), Uroxatral (alfuzosin HCl),
 Jalyn (dutasteride and tamsulosin HCl), or Rapaflo (silodosin).
Alpha-blockers are sometimes prescribed for prostate
problems or high blood pressure. In some patients, the use
of Sildenafil with alpha-blockers can lead to a drop in blood pressure or to fainting
With drug therapy, there’s a risk of side effects such as headaches, back pain or an upset stomach. Before taking any medication for erectile dysfunction it is important to ensure your doctor is ok with that decision. Medication may not work for all men, for instance, if you have diabetes or have previously had prostate surgery. ED medication might also have serious risks if you’re currently taking nitrates (commonly prescribed for chest pain), have heart disease or have low blood pressure.22
The dose of PDE5 inhibitor that you start with may vary with underlying medical conditions and medications that you are taking. Thus, it is important to review all medications (even over the counter medications) with your physician. Typically, one starts with a lower dose and increases as needed. Some medical conditions prevent going up to higher doses. You can review the drug prescribing information or consult with your doctor regarding the dose(s) that are appropriate for you.
Unfortunately, some patients may have an overly simplified understanding of the role of PDE5 inhibitors in ED management. Such patients may not expect or be willing to undergo a long evaluation and testing process to obtain a better understanding of their sexual problem, and they may be less likely to involve their partner in discussing their sexual relationship with the physician. They may expect to obtain medications through a phone call to their doctor or even over the Internet, with minimal or no physician contact at all.
It appears that testosterone has NOS-independent pathways as well. In one study, castrated rats were implanted with testosterone pellets and then divided into a group that received an NOS inhibitor (L-nitro-L-arginine methyl ester [L-NAME]) and a control group that received no enzyme. [24] The castrated rats that were given testosterone pellets and L-NAME still had partial erections, a result suggesting the presence of a pathway independent of NOS activity.

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.


This procedure is usually performed before and after injection of a smooth-muscle-relaxing medication into the penis, which normally should significantly increase the diameter of the penile arteries. The procedure itself is painless. Duplex ultrasonography is most useful in evaluating possible penile arterial disorders, but in those individuals considering surgery for problems with the arteries to the penis, a more invasive study, angiogram, is needed to identify the location of the damaged artery.
Surgery to repair arteries (penile arterial reconstructive surgery) can reduce impotence caused by obstructions that block the flow of blood to the penis. The best candidates for such surgery are young men with discrete blockage of an artery because of a physical injury to the pubic area or a fracture of the pelvis. The procedure is less successful in older men with widespread blockage of arteries.

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.)

Finally, gene therapy and stem cell research has widened the frontier of ED treatment proposed as possibility to even reverse ED. Specifically, gene therapy pertains to repairing the cause of ED by restoring defective gene function and/or altering the expression of the mutant gene (32). Most of the available data on gene therapy are in the animal model. However, a phase I clinical trial in men with ED undergoing intracavernous injection with a DNA plasmid carrying the alpha-subunit of the corporal smooth muscle Maxi-K channel showed promise in increased erectile function based on IIEF assessment sustained throughout the 3-month study period (122).

A cold slice of watermelon can do more than just satisfy thirst and hunger during the warm summer months; it can help with bedroom satisfaction. Citrulline, the amino acid found in high concentrations of watermelon, is found to improve blood flow to the penis. A 2011 study revealed men who suffered from mild to moderate ED and took L-citrulline supplementation showed an improvement with their erectile function and were very satisfied. Natural watermelon juice, or “nature’s Viagra,” can also be easier on the stomach, since taking pills like Viagra can cause nausea and diarrhea.

A malleable penile prosthesis usually consists of paired rods that are inserted surgically into each of the corpora cavernosa. The rods are stiff, and basically to have an erection, one bends them up and when finished with intercourse they are bent down. They do not change in length or width. The malleable penile prosthesis has the lowest risk of malfunction, however they have the least normal appearance.
ED usually has a multifactorial etiology. Organic, physiologic, endocrine, and psychogenic factors are involved in the ability to obtain and maintain erections. In general, ED is divided into 2 broad categories, organic and psychogenic. Although most ED was once attributed to psychological factors, pure psychogenic ED is in fact uncommon; however, many men with organic etiologies may also have an associated psychogenic component.
Since endothelial dysfunction, CVD and ED are closely associated in epidemiological studies, the question for clinicians is whether to recommend the man presenting with ED undergo a cardiovascular (CV) evaluation. Clearly, based on numerous studies, ED can be considered at least a ‘marker’ for possible further vascular disease or CVD.15 In their report, Vlachopoulos and coworkers make the point that the man presenting with ED, the clinician, is offered an opportunity to attempt to improve the health of the man by addressing lifestyle modification, and consider further vascular evaluation owing to the clear relationship between endothelial dysfunction, ED and CVD.19
When sexually stimulated/aroused, the nerves supplying the penis release a chemical, nitric oxide (NO). Nitric oxide is important because it stimulates the production of a chemical called cyclic guanosine monophosphate (cGMP). cGMP causes the muscle in arteries of the penis to relax and increase blood flow into the penis. NO is broken down in the body by phosphodiesterase enzymes. PDE5 inhibitors thus prevent the breakdown of NO and thus promote increased blood flow into the penis.
PDE5i medications are absolutely not to be taken by men with heart conditions who are taking nitrates such as nitroglycerine or isosorbide (Isordil, Ismo, Imdur). Those with serious heart disease, exertional angina (chest pain), and those taking multiple drugs for high blood pressure are advised to seek the advice of a heart specialist before beginning therapy with sildenafil.
Sexual functioning involves a complex interaction among biologic, sociocultural, and psychological factors, and the complexity of this interaction makes it difficult to ascertain the clinical etiology of sexual dysfunction. Before any diagnosis of sexual dysfunction is made, problems that are explained by a nonsexual mental disorder or other stressors must first be addressed. Thus, in addition to the criteria for erectile disorder, the following must be considered:

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In the Massachusetts Male Aging Study (MMAS) among a community-based survey of men aged 40-70 years, 52% of the men reported some degree of erectile difficulty. Complete ED, defined as the total inability to obtain or maintain suitable erections during sexual stimulation, as well as the absence of nocturnal erections (normal erections [four to six/night], which occur during sleep), occurred in 10% of the men in the study. Lesser degrees of mild and moderate ED occurred in 17% and 25% of participants.
Usually there will not be a specific treatment that will lead to the improvement of erectile dysfunction. However, there are treatments that will allow erections to happen and can be used to allow sexual activity to take place. There are three main types of treatments: non-invasive treatments such as tablet medicines and external devices (e.g. vacuum device); penile injections; or for men who have not had success with other treatments, surgery may be an option.
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