Inside the cell, NOS catalyzes the oxidation of L-arginine to NO and L-citrulline. Endogenous blockers of this pathway have been identified. The gaseous NO that is produced acts as a neurotransmitter or paracrine messenger. Its biologic half-life is only 5 seconds. NO may act within the cell or diffuse and interact with nearby target cells. In the corpora cavernosa, NO activates guanylate cyclase, which in turn increases cyclic guanosine monophosphate (cGMP). Relaxation of vascular smooth muscles by cGMP leads to vasodilation and increased blood flow.
I have no idea why your boyfriend's junk is stuck in the junkyard. He's just 25, in the prime of his penis. It's fairly rare for a guy that young to go from instant erection to shy willy. One study found that just 2 percent of men experienced erectile dysfunction before the age of 40. If it's a short-term thing, it could be simple: Maybe he just needs to get more sleep or have fewer drinks.
The health care provider will ask about the firmness and duration of erections at different times (e.g., sex with partners, erections after sleep). Discussing sexual dysfunction with a health care provider is very important because many conditions causing it can be successfully treated. If a man has no diseases that cause ED and can have an erection with masturbation or early morning awakening, he likely has ED due to psychological causes.

The dorsal artery provides for engorgement of the glans during erection, whereas the bulbourethral artery supplies the bulb and the corpus spongiosum. The cavernous artery effects tumescence of the corpus cavernosum and thus is principally responsible for erection. The cavernous artery gives off many helicine arteries, which supply the trabecular erectile tissue and the sinusoids. These helicine arteries are contracted and tortuous in the flaccid state and become dilated and straight during erection. [9]
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Surgery of the penile venous system, generally involving venous ligation, has been reported to be effective in patients who have been demonstrated to have venous leakage. However, the tests necessary to establish this diagnosis have been incompletely validated; therefore, it is difficult to select patients who will have a predictably good outcome. Moreover, decreased effectiveness of this approach has been reported as longer term followups have been obtained. This has tempered enthusiasm for these procedures, which are probably therefore best done in an investigational setting in medical centers by surgeons experienced in these procedures and their evaluation.
Metabolism (breakdown) of vardenafil can be slowed by aging, liver disease, and concurrent use of certain medications (such as erythromycin [an antibiotic], ketoconazole [Nizoral, a medication for fungal/yeast infections], and protease inhibitors [medications used to treat AIDS]). Slowed breakdown allows vardenafil to accumulate in the body and potentially increase the risk for side effects. Therefore, in men over 65 years of age with liver disease, or who are also taking medication(s) that can slow the breakdown of vardenafil, the doctor will initiate vardenafil at low doses to avoid its accumulation. For example,
The recommended starting dose of tadalafil for use as needed for most patients is 10 mg taken orally approximately one hour before sexual activity. A doctor may adjust the dose higher to 20 mg or lower to 5 mg depending on efficacy and side effects. Doctors recommended that patients take tadalafil no more frequently than once per day. Some patients can take tadalafil less frequently since the improvement in erectile function may last 36 hours. Patients may take tadalafil with or without food. Tadalafil is currently the only PDE5 inhibitor that is FDA-approved for daily use for erectile dysfunction and is available in 2.5 mg or 5 mg dosages for daily use.
Obesity and metabolic syndrome can cause changes in blood pressure, body composition, and cholesterol which may lead to ED. Other conditions that may contribute to erectile dysfunction include Parkinson’s, multiple sclerosis, Peyronie’s disease, sleep disorders, alcoholism, and drug abuse. Taking certain medications can also increase your risk for ED.

Normal erectile function depends on the release of NO and endothelial-dependent vasodilation of the penile arteries. The ‘artery size’ hypothesis, first described by Dr Montorsi, offers an explanation why men are more likely to develop ED before a myocardial infacrtion. It is believed that atherosclerosis affects all vascular beds equally but smaller arteries are more likely to become occluded than larger arteries.31 32 The penile arteries are 1–2 mm while the coronary arteries are 3–4 mm. Thus, the same degree of endothelial dysfunction and atherosclerosis is more likely to occlude blood flow in the penile arteries compared with the coronary arteries. The penile arteries therefore serve as a sensitive indicator for subsequent CVD. This theory is supported by the fact that ED occurs approximately 3 years prior to cardiac symptoms in virtually all patients with chronic coronary syndrome whereas patients with acute coronary syndrome have a much lower prevalence of sexual dysfunction.32
In the short term, alcohol relaxes muscles in the penis, letting blood to flow in (which is a good thing). However, alcohol also prevents other blood vessels from closing and trapping all the extra blood. Erections depend on trapping increased blood flow in the erectile tissue of the penis. If you don’t trap that extra blood, you don’t get an erection. In the long run, excessive alcohol consumption can cause liver scarring, high blood pressure, and can damage your blood vessels resulting in erectile dysfunction.
The inflatable type of device consists of cylinders that are implanted in the corpora cavernosa, a fluid reservoir implanted in the abdomen, and a pump placed in the scrotum. The man squeezes the pump to move fluid into the cylinders and cause them to become rigid. (He reverses the process by squeezing the pump again.) While these devices allow for intermittent erections, they have a slightly higher malfunction rate than the silicon rods.
But if the blood flow is weak here, it is highly likely that it is also weak in arteries supplying the heart, raising the risk of a heart attack. In fact, some studies suggest that women with heart disease may also suffer sexual dysfunction: the clitoris, like the penis, is a vascular organ, and also relies on healthy blood flow for successful orgasms.
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.
As is true in so many medical conditions, lifestyle modifications, considered first-line therapy, can have a salutary effect in ED management, and men should be encouraged to make the necessary changes to the benefit of their sexual function and to their overall health as well. Despite the benefits of behaviour modification, men presenting with ED want the physician to help with measures that can have an immediate impact.
Between 10 and 88% of patients diagnosed with cancer experience sexual problems following diagnosis and treatment. The prevalence varies according to the location and type of cancer, and the treatment modalities used. Sexuality may be affected by chemotherapy, alterations in body image due to weight change, hair loss or surgical disfigurement, hormonal changes, and cancer treatments that directly affect the pelvic region.

Before taking any medication for erectile dysfunction, including over-the-counter supplements and herbal remedies, get your doctor's OK. Medications for erectile dysfunction do not work in all men and might be less effective in certain conditions, such as after prostate surgery or if you have diabetes. Some medications might also be dangerous if you:
To start with, ED is NOT in your head. You can’t simply will yourself to get an erection, no matter how much you try. Studies show over 80% of ED cases are caused by a treatable physical disorder. Diseases such as diabetes, high blood pressure, and high cholesterol are common causes. Even a perfectly healthy man can develop ED after a brain or spinal cord injury. ED can be a side effect of certain medications, too.  Read more on our Causes of ED page.

Psychological processes such as depression, anxiety, and relationship problems can impair erectile functioning by reducing erotic focus or otherwise reducing awareness of sensory experience. This may lead to inability to initiate or maintain an erection. Etiologic factors for erectile disorders may be categorized as neurogenic, vasculogenic, or psychogenic, but they most commonly appear to derive from problems in all three areas acting in concert.
I always made sure to satisfy my woman first, from the start of our marriage. When I started having issues with ED a few years ago, I talked to her about it and asked for her to be understanding and also that I needed a lot of the things sexually that she had not really given me much of, regardless of how much pampering or pleasing I did for her. She agreed, but never really stepped it up despite me talking to her about it every few weeks trying to salvage my own interest in sex. I had chased her constantly for over 10 years, then after the psychological effects of ED took their toll and she never really followed through helping me, my sex drive just tanked. I stopped chasing her, then after a little while she slowly started wanting it enough to initiate. Even then, she still wants the same sex as before, without the things I want being a regular part of it. My sex drive is still very low, and I still make an effort, but I can tell that my interest in sex is just deteriorating every time I have an ED episode and feel my desires being neglected. Each time, it just makes me less interested in continuing to try "serve" her because she does not return the favor much. The idea of spending so much effort doing "other stuff" while my wants and desires are barely recognized makes sex sound as exciting as mowing the yard to me now days.

Erection is a vascular event. The penis becomes rigid when blood flow to the corpora cavernosa increases sixfold and venous outflow is physiologically impeded. Penile perfusion is governed by three organ systems—the neurologic, circulatory, and endocrinologic systems—each necessary for potency. The neurologic system accounts for vasodilation and venoconstriction of the corporal blood vessels so that blood is shunted to the erectile tissues; the circulatory system provides adequate blood flow to the hypogastric-cavernous bed, a distal branch off the internal iliac vessels; and the endocrine system, mediated by testosterone, plays a permissive role through mechanisms that have yet to be elucidated.


Despite the accumulation of a substantial body of scientific information about erectile dysfunction, large segments of the public -- as well as the health professions -- remain relatively uninformed, or -- even worse -- misinformed, about much of what is known. This lack of information, added to a pervasive reluctance of physicians to deal candidly with sexual matters, has resulted in patients being denied the benefits of treatment for their sexual concerns. Although they might wish doctors would ask them questions about their sexual lives, patients, for their part, are too often inhibited from initiating such discussions themselves. Improving both public and professional knowledge about erectile dysfunction will serve to remove those barriers and will foster more open communication and more effective treatment of this condition.
Some men should not take PDE5 inhibitors. They can cause hypotension (abnormally low blood pressure that can lead to fainting and even shock) when given to patients who are taking nitrates (medications taken for heart disease). Therefore, patients taking nitrates daily should not take any of the PDE5 inhibitors. Nitrates relieve angina (chest pain due to insufficient blood supply to the heart muscle because of narrowing of the coronary arteries); these include nitroglycerine tablets, patches, ointments, sprays, and pastes, as well as isosorbide dinitrate and isosorbide mononitrate. Other nitrates such as amyl nitrate and butyl nitrate also are in some recreational drugs called "poppers."

Smoking damages blood vessels, inhibiting blood flow throughout the body ... and I mean throughout the body. While studies have found that men with erectile problems only make up 20 percent of the general population, 40 percent of men with erectile problems are smokers. And a 2011 study of a group of male smokers with erectile problems found that 75 percent of them saw those erectile problems disappear after they quit.


It is necessary to identify the causes of worry and try to remove these. They could include concern about personal relationships, work, family problems, health or even sexual “performance” with a new or old partner. It is often said that the brain is the biggest sex organ of them all – if it is too busy with other things, it will not be involved in arousal and the erection that follows.
It doesn't really matter what they are — sexual turnoffs vary wildly from person to person. But if the person you're getting it on with is doing stuff that's taking you out of the mood — even if it's stuff you feel like you're supposed to enjoy — it's time to swallow your pride and say something. Keeping it a secret might be saving you an awkward conversation in the short term, but in the long term, it could be seriously undermining your sex life. 

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.


Erectile dysfunction is the inability to develop or maintain an erection that is rigid enough to allow penetration of the vagina, and therefore functional sexual intercourse. Generally, the term erectile dysfunction is applied if this occurs frequently (75% of the time) over a significant period if time (several weeks to months). If this is the case, the term impotence may also be used.
The association of CVD and ED was noted in 1997 as one analysed the results of the MMAS. In this landmark study, 1709 men aged 40–70 years were enrolled between 1987 and 1989. A follow-up some 10 years later revealed a striking relationship between ED and CVD. In this study, it became clear that the risk factors for ED were very similar to those of CVD, such as diabetes mellitus, smoking and dyslipidaemia.18

The risk of impotence increases with age. It is four-fold higher in men in their 60s compared with those in their 40s according to a study published in the Journal of Urology (2000;163:460-463). Men with less education are also more likely to experience impotence, perhaps because they tend to have less healthy lifestyles, eat a less healthy diet, drink more and exercise less. Physical exercise tends to lessen the risk of impotence.

Alprostadil self-injection. With this method, you use a fine needle to inject alprostadil (Caverject Impulse, Edex) into the base or side of your penis. In some cases, medications generally used for other conditions are used for penile injections on their own or in combination. Examples include papaverine, alprostadil and phentolamine. Often these combination medications are known as bimix (if two medications are included) or trimix (if three are included).
Thanks to over a decade of primetime television commercials, most of us can name at least one drug that treats erectile problems. However, far fewer of us can name drugs that may actually cause the problem. In reality, MedlinePlus reported that there are far more of these, and even common drugs such those to treat depression and heartburn can make it difficult to get an erection.
The motivation and expectations of the patient and his partner and education of both are critical in determining which therapy is chosen and in optimizing its outcome. If single therapy is ineffective, combining two or more forms of therapy may be useful. Penile prostheses should be placed only after patients have been carefully screened and informed. Vascular surgery should be undertaken only in the setting of clinical investigation and extensive clinical experience. With any form of therapy for erectile dysfunction, long-term followup by health professionals is required to assist the patient and his partner with adjustment to the therapeutic intervention. This is particularly true for intracavernosal injection and vacuum constriction therapies. Followup should include continued patient education and support in therapy, careful determination of reasons for cessation of therapy if this occurs, and provision of other options if earlier therapies are unsuccessful.

Cosgrove et al reported a higher rate of sexual dysfunction in veterans with posttraumatic stress disorder (PTSD) than in veterans who did not develop this problem. [42] The domains on the International Index of Erectile Function (IIEF) questionnaire that demonstrated the most change included overall sexual satisfaction and erectile function. [43, 44] Men with PTSD should be evaluated and treated if they have sexual dysfunction.
There have been some studies to suggest that a placebo effect that improves ED may work for some men. One study found that men taking an oral placebo pill showed as much improvement in ED symptoms as men who took actual medication to improve ED. Conversely, men who were given therapeutic suggestions to improve ED did not see signs of symptom improvement.
The motivation and expectations of the patient and his partner and education of both are critical in determining which therapy is chosen and in optimizing its outcome. If single therapy is ineffective, combining two or more forms of therapy may be useful. Penile prostheses should be placed only after patients have been carefully screened and informed. Vascular surgery should be undertaken only in the setting of clinical investigation and extensive clinical experience. With any form of therapy for erectile dysfunction, long-term followup by health professionals is required to assist the patient and his partner with adjustment to the therapeutic intervention. This is particularly true for intracavernosal injection and vacuum constriction therapies. Followup should include continued patient education and support in therapy, careful determination of reasons for cessation of therapy if this occurs, and provision of other options if earlier therapies are unsuccessful.
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
I always made sure to satisfy my woman first, from the start of our marriage. When I started having issues with ED a few years ago, I talked to her about it and asked for her to be understanding and also that I needed a lot of the things sexually that she had not really given me much of, regardless of how much pampering or pleasing I did for her. She agreed, but never really stepped it up despite me talking to her about it every few weeks trying to salvage my own interest in sex. I had chased her constantly for over 10 years, then after the psychological effects of ED took their toll and she never really followed through helping me, my sex drive just tanked. I stopped chasing her, then after a little while she slowly started wanting it enough to initiate. Even then, she still wants the same sex as before, without the things I want being a regular part of it. My sex drive is still very low, and I still make an effort, but I can tell that my interest in sex is just deteriorating every time I have an ED episode and feel my desires being neglected. Each time, it just makes me less interested in continuing to try "serve" her because she does not return the favor much. The idea of spending so much effort doing "other stuff" while my wants and desires are barely recognized makes sex sound as exciting as mowing the yard to me now days.
Having learned a great deal more about erectile dysfunction including its risk factors and causes, you should be equipped to assess your own erectile function. If you have experienced erectile issues or you have some of the risk factors mentioned above, it may be worth making a trip to your doctor’s office. If you choose to seek help, give your doctor as much information as you can about your symptoms including their frequency and severity as well as the onset. With your doctor’s help, you can determine the best course of treatment to restore sexual function.
The severity of ED has been correlated with the extent of CVD. Banks et al reported that the risk of future CV events increased progressively according to ED severity.28 This was shown in both men with and without known CVD at baseline and after controlling for confounders. Solomon and colleagues found an inverse correlation between international index of erectile function (IIEF) scores and plaque burden seen on coronary angiography.29 In addition, Yaman et al demonstrated a significant correlation between ED severity on IIEF questionnaires and coronary artery calcification.30

The inflatable type of device consists of cylinders that are implanted in the corpora cavernosa, a fluid reservoir implanted in the abdomen, and a pump placed in the scrotum. The man squeezes the pump to move fluid into the cylinders and cause them to become rigid. (He reverses the process by squeezing the pump again.) While these devices allow for intermittent erections, they have a slightly higher malfunction rate than the silicon rods.
Stiffy Solution: Again, saying "stop being so stressed out so you can get boners again" is easier said than done — but a lot of people find sexual dysfunction to be a stronger motivator to live a healthier lifestyle than the threat of, say, a heart attack down the road; so there's a chance that this could actually be a good thing in the long run for your boo, if it helps him take his stress seriously. Relaxation techniques like yoga, exercise, meditation, tai chi, and getting adequate sleep can all lessen the impact of stress on your body (and your dong).
A number of herbs have been promoted for treating impotence. The most widely touted herbs for this purpose are Coryanthe yohimbe (available by prescription as yohimbine, with the trade name Yocon) and gingko (Gingko biloba), although neither has been conclusively shown to help the condition in controlled studies. In addition, gingko carries some risk of abnormal blood clotting and should be avoided by men taking blood thinners such as coumadin. Other herbs promoted for treating impotence include true unicorn root (Aletrius farinosa), saw palmetto (Serenoa repens), ginseng (Panax ginseng), and Siberian ginseng (Eleuthrococcus senticosus). Strychnos Nux vomica has been recommended, especially when impotence is caused by excessive alcohol, cigarettes, or dietary indiscretions, but it can be very toxic if taken improperly, so it should be used only under the strict supervision of a physician trained in its use.
Another study compared the response of surgically and medically castrated rabbits to vardenafil with that of control rabbits. [22] Castrated rabbits did not respond to vardenafil, whereas noncastrated rabbits did respond appropriately. This result suggests that a minimum amount of testosterone is necessary for PDE5 inhibitors to produce an erection.
My boyfriend has a hard time getting and staying hard. It's obviously a difficult situation to talk about, but he says he feels pressure when he's with me (versus previous random hookups he wasn't invested in), so he psyches himself out. When we do have sex, I'm almost always really satisfied and I care a lot about him, both things I express in and outside of the bedroom. But the situation seems to be only getting worse. We've stopped having sex during the week because our busy lives mean we don't have an hour or more to devote to sex (which is sometimes what it takes), or we can't have sex at all because of what he's experiencing. I'm afraid this is going to continue to get worse, not only sexually but emotionally in our relationship. How can I help him fix this, and reassure him in the meantime that I care about him and want to support him?
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.

Aging, liver and kidney problems, and concurrent use of certain medications (such as erythromycin [an antibiotic] and protease inhibitors for HIV) slows the metabolism (breakdown) of sildenafil. Slowed breakdown allows sildenafil to accumulate in the body and potentially may increase the risk of side effects. Therefore, in men over 65 years of age, in men with significant kidney and liver disease, and in men who also are taking medications called protease inhibitors, the doctor will initiate sildenafil at a lower dose (25 mg) to avoid accumulation of sildenafil in the body. A protease inhibitor ritonavir (Norvir) is especially potent in increasing the accumulation of sildenafil, thus men who are taking Norvir should not take sildenafil doses higher than 25 mg and at a frequency of no greater than once in 48 hours. Other medications that may affect the level of sildenafil include erythromycin and ketoconazole.

You’ve probably heard of Viagra, but it’s not the only pill for ED. This class of drugs also includes Cialis, Levitra,  Staxyn, and Stendra. All work by improving blood flow to the penis during arousal. They're generally taken 30-60 minutes before sexual activity and should not be used more than once a day. Cialis can be taken up to 36 hours before sexual activity and also comes in a lower, daily dose. Staxyn dissolves in the mouth. All require an OK from your doctor first for safety.
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