The penis is composed of three cylinders: two on the top, the corpora cavernosa and one on the bottom, the corpus spongiosum. All of these are involved in the process of an erection. The corpora cavernosa are composed of potential spaces that can distend with blood, causing rigidity of the penile shaft. The corpus spongiosum is important for rigidity of the glans of the penis. When aroused, stimulated chemicals are released from the nervous system (nitric oxide is one) that stimulate the arteries to the penis to relax and increase blood flow into the penis. These potential spaces, like a sponge, can expand when more blood flow comes in the penis. Each corpora cavernosa is surrounded by an outer coating the tunica albuginea. When the penis fills with blood, these potential spaces, the sinusoids, compress the veins in the corpora against the side of the tunica albuginea, thus preventing blood from leaving the penis. It is this compression of the veins that allows for the erection to become fully rigid.
These are not currently approved by the FDA for ED management, but they may be offered through research studies (clinical trials). Patients who are interested should discuss the risks and benefits (informed consent) of each, as well as costs before starting any clinical trials. Most therapies not approved by the FDA are not covered by government or private insurance benefits.
As blood flows into the penis, the corpora cavernosa swell, and this swelling compresses the veins (blood vessels that drain the blood out of the penis) against the tunica albuginea. Compression of the veins prevents blood from leaving the penis. This creates a hard erection. When the amount of cGMP decreases by the action of a chemical called phosphodiesterase type 5 (PDE5), the muscles in the penis tighten, and the blood flow into the penis decreases. With less blood coming into the penis, the veins are not compressed, allowing blood to drain out of the penis, and the erection goes down.
Though psychological causes of erectile dysfunction may be more complex than medical causes, they are still treatable. You should know, however, that resolving psychological impotence may not be quite as simple as taking Viagra (sildenafil citrate). ED drugs are designed to sidestep the physiological causes for ED such as low blood pressure or vascular damage – they won’t help you with issues of anxiety, stress, or low self-esteem. The best treatment for psychological ED will address the problem at its root.
Erectile dysfunction is a common problem for more than half of men with diabetes. Musicki says that an estimated "50 percent to 75 percent of diabetic men have erectile dysfunction to some degree, [a rate] about threefold higher than in non-diabetic men."  This is not the same type of erectile dysfunction seen in non-diabetics, and it is less effectively treated with conventional drugs like Viagra. 
Impotence, also known as erectile dysfunction or ED, is a condition in which a man is unable to get or hold an erection long enough to have a satisfactory sex life. Impotence is a common problem, affecting up to half of Australian men between the ages of 40 and 70 years. The risk of developing erectile dysfunction increases as you get older.In the past, doctors considered impotence to be a mainly psychological problem, caused by performance anxiety or stress. Now, doctors know that many cases of impotence have a physical cause, which usually can be treated. Often, a combination of physical and psychological factors contributes to erectile dysfunction.Physical causes of impotencePhysical causes of impotence can include:problems with blood to flow into and out of the penis;damage to the nerves that send signals from the body’s central nervous system to the penis; and, more rarely,a deficiency in testosterone or other hormones.Some medicines can contribute to impotence, as can some types of surgery and radiotherapy treatments.Blocked blood vessels to the penisA very common cause of impotence is when blood flow into the penis is reduced. This can be due to atherosclerosis, also known as hardening of the arteries. In atherosclerosis, the arteries are clogged and narrowed, resulting in reduced blood flow.Risk factors for atherosclerosis include:high cholesterol;high blood pressure;obesity;sleep apnoea;diabetes; andsmoking.If your erection problems are caused by atherosclerosis, there is a chance that the arteries in other parts of your body (e.g. the coronary arteries that supply your heart) are also affected by atherosclerosis. In fact, erection problems may be the first sign that you are at risk of coronary heart disease.Because the arteries to the penis are narrower than those to the heart, you may develop symptoms of erectile dysfunction before you experience any symptoms of heart disease, such as angina. So seeing your doctor about erection problems may be important for your overall physical health.Impotence can also be caused by a blood clot that prevents enough blood from flowing into the penis to cause an erection.Venous leakageIn some men, blood can flow in to the penis easily, but the problem is that it leaks out again, so an erection cannot be sustained. This is called venous leakage. Doctors aren’t certain of the cause of venous leakage, but they can perform surgery to help repair it.Medicines that can cause impotenceMany medicines can cause erection problems as a side effect, including:diuretics (sometimes known as ‘water tablets’ - often used for high blood pressure);high blood pressure medications;cholesterol-lowering medicines (including statins);some types of antipsychotics;antidepressants;cancer treatments;some medicines used to treat heartburn and stomach ulcers;antihistamines;some pain medicines; andcertain epilepsy medications.If you experience impotence after starting a new medication, tell your doctor, who may be able to prescribe a different medicine for you. Don’t stop taking a medicine without first consulting your doctor. You should also tell your doctor about any over-the-counter medicines or complementary remedies you may be taking.The following table contains a list of specific medicines that may cause or contribute to erectile dysfunction. This list may not cover all types of medicines that can cause erectile dysfunction, so always ask your doctor if you are in doubt. Also, for some of these medicines ED is a very rare side effect. Most men taking these medicines do not experience erectile dysfunction.Medicines that may cause erectile dysfunctionType of medicineExamplesACE inhibitorscaptopril (Capoten), enalapril (Renitec), perindopril (Perindo), ramipril (Tritace), and othersAntidepressantsamitriptyline (Endep), clomipramine (Anafranil), desvenlafaxine (Pristiq), fluoxetine (Prozac), paroxetine (Aropax), sertraline (Zoloft), venlafaxine (Altven, Efexor), and othersAnti-epilepticsclonazepam (Rivotril), pregabalin (Lyrica)Antifungalsitraconazole (Sporanox)Anti-ulcer drugscimetidine (Magicul), nizatidine (Tazac), ranitidine (Zantac), and othersBeta-blockerspropranolol (Inderal), metoprolol (Betaloc, Lopresor), and othersOther blood pressure-lowering medicinesclonidine (Catapres), lercanidipine/enalapril (Zan-Extra), losartan (Cozaar), perindopril/amlodipine (Coveram), olmesartan/amlodipine (Sevikar), telmisartan/amlodipine (Twynsta), valsartan/hydrochlorothiazide (Co-Diovan)Calcium-channel blockersdiltiazem (Cardizem), felodipine (Plendil), nifedipine (Adalat)Cholesterol-lowering drugsatorvastatin (Lipitor), ezetimibe/simvastatin (Vytorin), fluvastatin (Lescol, Vastin), gemfibrozil (Ausgem), pravastatin (Pravachol), simvastatin (APO-simvastatin, Lipex, Zocor), and othersDiuretics ('water tablets')bumetanide (Burinex), chlorthalidone (Hygroton), spironolactone (Aldactone), and othersSchizophrenia drugsamisulpride (Solian, Sulprix), haloperidol (Haldol, Serenace), olanzapine (Lanzek, Ozin, Zypine, Zyprexa), paliperidone (Invega), risperidone (Rispa, Risperdal), ziprasidone (Zeldox)Combination cholesterol-lowering and anti-hypertensiveamlodipine/atorvastatin (Caduet, Cadatin)Pain medicinesfentanyl (Denpax, Durogesic), hydromorphone (Jurnista), morphine (Momex SR, MS Contin), oxycodone (OxyContin, OxyNorm, Targin), tramadolMiscellaneousoestrogens, antiandrogens, anticancer drugs and some chemotherapy treatments, baclofen (Clofen, Lioresal); cyproterone (Androcur, Cyprohexal, Cyprostat), degarelix (Firmagon), etoricoxib (Arcoxia), finasteride (Proscar and Propecia), flutamide (Flutamin), rotigotine (Neupro), triptorelin (Diphereline)*The names in brackets are just some examples of the trade names each specific medicine is marketed under in Australia. The medicine may also be known by other trade names.Diabetes and erectile dysfunctionMen who have diabetes have a higher risk of developing impotence than other men. Diabetes contributes to impotence because it can damage blood vessels and cause a type of nerve damage known as peripheral neuropathy.Hormones and impotenceLow levels of the male hormone, testosterone, are more commonly linked to a lowered sex drive, rather than impotence itself. Only a small percentage of cases of impotence are caused by hormone deficiency.Low testosterone levels may be the result of a condition called hypogonadism, in which the testicles don’t produce enough testosterone. More rarely, low testosterone can be caused by the pituitary (a small gland at the base of the brain) not secreting sufficient hormones to stimulate the testes to produce testosterone. The pituitary is also sometimes affected by small benign (non-cancerous) tumours that secrete prolactin, another hormone that can cause impotence.Mildly decreased levels of testosterone are often not due to specific testicular or pituitary problems, but rather stress or depression. In this situation, testosterone replacement is rarely of any benefit.Other hormone problems, including thyroid disease, can also cause impotence.Prostate cancer and erectile dysfunctionThe advanced stages of prostate cancer can affect the nerves and arteries that are vital for an erection.Radiation treatment for prostate cancer can harm the erectile tissues of the penis, and prostate cancer surgery can cause nerve or artery damage to the penis.Treatment for advanced prostate cancer often includes medicines that counteract testosterone, and commonly cause erectile dysfunction as well as loss of sexual interest.Peyronie’s diseasePeyronie’s disease is an uncommon condition that affects a man’s sex life because his penis curves abnormally and causes pain when he has an erection. He might also be unable to have a hard erection. The curvature of the penis is caused by a scar, called a plaque, that forms in the penis.Other physical causes of impotenceSeveral other factors and conditions can contribute to erectile dysfunction, including the following.Depression. Many men find that when they’re suffering from depression, they lose interest in sex and can’t get or keep an erection. Asking your doctor for treatments for depression may help alleviate your erection problems as well.Smoking contributes to vascular disease (disease of the blood vessels), so it can contribute to erectile dysfunction by affecting blood flow to the penis. Giving up smoking often has a beneficial effect on erectile function.Excessive alcohol use. Alcoholism can cause permanent nerve damage, resulting in impotence. This nerve damage is called peripheral neuropathy. Long-term alcohol use can impair the liver’s ability to function, resulting in a hormone imbalance in which a man has too much of the female sex hormone, oestrogen. On a day-to-day level, alcohol dulls the central nervous system, adversely affecting sexual response.Illicit drug use. Illicit drugs such as marijuana, cocaine, heroin, barbiturates, and amphetamines act on the central nervous system, impairing the body’s ability to respond sexually.Certain exercises. Nerve and artery damage can be caused by prolonged cycling, rodeo riding, or use of a rowing machine, resulting in the inability to get an erection. Often, minimising the use of hard bicycle seats and exercise machine seats, as well as correct positioning of the seat, will help restore sexual function.Surgery to organs near the nerve pathways of the penis, such as the bladder, rectum and prostate, can cause nerve or artery damage to the penis, resulting in the inability to have an erection.Injuries. Impotence can be caused by spinal cord injury; injury to your sex organs; or a pelvic fracture, which can cause damage to the nerves of the penis, or damage the blood vessels, resulting in reduced blood flow to the penis.Conditions affecting the nervous system. Multiple sclerosis (MS) and other degenerative diseases of the nervous system, such as Parkinson’s disease, can damage the nerves involved in erections.Psychological causes of impotenceMost cases of impotence have physical causes, but, in some men, psychological factors are the main contributors to impotence.Impotence that’s triggered by psychological factors is more common in men who are sexually inexperienced. Psychological erectile dysfunction may only occur when you’re with just one particular person. You’re also more likely to have morning erections, and be able to have an erection when you masturbate, than men whose impotence has a physical cause.Here are some psychological factors that can have an impact on your erections.Stress and anxietyWhen you’re stressed and focusing on other issues apart from sex, you might find that you don’t want to have sex as often and there might be a drop in your ability to perform when you do try. You might find that tackling the source of your stress can have benefits in the bedroom as well.Fear of failureAnxiety about your sexual prowess (commonly called performance anxiety) can, in itself, contribute to failure. By putting pressure on yourself, you become too anxious to get an adequate erection.Most men experience isolated episodes of erectile failure. Even when the transient physical cause has passed, anxiety that it may recur is sufficient to prevent erection. Anxiety, whether about something specifically sexual or part of a wider anxiety syndrome, is never helpful to good sexual function.Problems with your relationship and impotenceImpotence may be a manifestation of a poor relationship, or a problematic time in a relationship. Sexual boredom, tension or anger among partners, and lack of intimacy and communication are all possible triggers of erectile dysfunction. In these cases, seeing a counsellor may help.It’s worth remembering that impotence is a complex medical condition, which may have more than one cause. For example, if impotence is the result of a side effect of medicine or an underlying disease, the anxiety caused by lack of performance may perpetuate the erectile dysfunction even after the physical cause has been dealt with.Almost any chronic (ongoing) physical or mental health disorder, including those with no direct effect on penile nerves or blood supply, can have a powerful effect on sexuality, sexual self-image and erectile function.If you’re worried about your sexual response or the quality of your erections, don’t be afraid to talk to your doctor, who has access to treatments that can help. Last Reviewed: 16 December 2016
Since the decrease in T levels is often a consequence of obesity or weight gain (51), the milestone of treating testosterone deficiency in obese men is encouraging substantial lifestyle changes, including physical activity and weight loss. In fact, it is universally recognized that a low calorie diet or bariatric surgery can induce a significant increase in T plasma levels, reaching 10 nmol/L with the most invasive surgical procedures (62). Weight loss-induced T rise is more evident in young individuals (62), and, therefore, it must be strongly recommended in this age band.
Sildenafil is available as oral tablets at doses of 25 mg, 50 mg, and 100 mg. Patients should take sildenafil approximately one hour before sexual activity. In some men, the onset of action of the drug may be as early as 11-20 minutes. It's best for men to take sildenafil on an empty stomach for best results since absorption and effectiveness of sildenafil can be diminished if it is taken shortly after a meal, particularly a meal that is high in fat. Sildenafil and the other PDE5 inhibitors don't cause an immediate erection. Sexual stimulation is necessary for these medications to work.
Erectile dysfunction (ED) is commonly called impotence. It’s a condition in which a man can’t achieve or maintain an erection during sexual performance. Symptoms may also include reduced sexual desire or libido. Your doctor is likely to diagnose you with ED if the condition lasts for more than a few weeks or months. ED affects as many as 30 million men in the United States.

With that said, the only data we’re going to focus on here are the results of large, nationally representative sex surveys because they offer the best source of information when it comes to trying to establish realistic prevalence rates and how they might have changed over time. Data from convenience samples of college students just aren’t reliable enough for these purposes.


Other medical therapies under evaluation include ROCK inhibitors and soluble guanyl cyclase activators. Melanocortin receptor agonists are a new set of medications being developed in the field of erectile dysfunction. Their action is on the nervous system rather than the vascular system. PT-141 is a nasal preparation that appears to be effective alone or in combination with PDE5 inhibitors. The main side effects include flushing and nausea. These drugs are currently not approved for commercial use.
The number of symptoms reported appeared to be a function of the amount of alcoholic beverage consumed. The chance of developing sexual dysfunctions appears to increase with increasing quantity of alcohol consumed. Higher levels of alcohol intake may result in greater neurotoxic effects. It has been reported that heavy alcohol use may contribute to a reversible vagal neuropathy, which is perhaps reversible on abstinence.[17] However, chronic heavy use of alcohol is also known to significantly alter gonadal hormones.[9]
Cardiovascular diseases account for nearly half of all cases of erectile dysfunction in men older than 50 years. Cardiovascular causes include those that affect arteries and veins. Damage to arteries that bring blood flow into the penis may occur from hardening of the arteries (atherosclerosis) or trauma to the pelvis/perineum (for example, pelvic fracture, long-distance bicycle riding).
Not only can guilt affect your ability to perform sexually, but so can low self-esteem. The correlation between erectile dysfunction and low self-esteem seems obvious from one direction – an inability to perform in the bedroom can cause you to feel bad about yourself. But how does low self-esteem cause ED? Self-esteem is defined as, “confidence in one’s own worth or abilities.”
Aging: There are two reasons why older men are more likely to experience erectile dysfunction than younger men. First, older men are more likely to develop diseases (such as heart attacks, angina, cardiovascular disease, strokes, diabetes mellitus, and high blood pressure) that are associated with erectile dysfunction. Second, the aging process alone can cause erectile dysfunction in some men by causing changes in the muscle and tissue within the penis.
The physical examination can reveal clues for physical causes of erectile dysfunction. A doctor will perform an assessment of BMI and waist circumference to evaluate for abdominal obesity. A genital examination is part of the evaluation of erectile dysfunction. The examination will focus on the penis and testes. The doctor will ask you about penile curvature and will examine the penis to see if there are any plaques (hard areas) palpable. The doctor will examine the testes to make sure they are in the proper location in the scrotum and are normal in size. Small testicles, lack of facial hair, and enlarged breasts (gynecomastia) can point to hormonal problems such as hypogonadism with low testosterone levels. A health care provider may check pulses in your groin and feet to determine if there is a suggestion of hardening of the arteries that could also affect the arteries to the penis.
There are two kinds of surgery for ED: one involves implantation of a penile prosthesis; the other attempts vascular reconstruction. Expert opinion about surgical implants has changed during recent years; today, surgery is no longer so widely recommended. There are many less-invasive and less-expensive options, and surgery should be considered only as a last resort.
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