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,

"Erectile dysfunction can be a very serious issue because it's a marker of underlying cardiovascular disease, and it often occurs before heart conditions become apparent. Therefore, men should consider improving their weight and overall nutrition, exercise more, drink less alcohol and have a better night's sleep, as well as address risk factors such as diabetes, high blood pressure and cholesterol.
Poor cardiovascular health reduces your body’s ability to deliver blood needed to produce erections. In a study published in 2004, researchers followed male participants for 25 years. The researchers found that heart disease risk factors predicted which men were most at risk of future ED. Numerous studies have strongly tied four major cardiovascular risk factors to ED:
A 2013 study published in The Journal of Sexual Medicine evaluated 439 men for erectile dysfunction and compared ED causes and frequency in men 40 or younger to men over 40. They found that 26 percent of the younger men had ED. Although these men were healthier and had higher levels of testosterone than the older men, they were more likely to be smokers or to have used illicit drugs. In almost half of the younger men with ED, the ED was considered severe.
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.
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.
In patients with low testosterone, testosterone treatment can improve libido and erectile dysfunction, but many men still may need additional oral medications such as sildenafil, vardenafil, or tadalafil. Some studies suggest that men with ED and low testosterone may respond better to PDE5 inhibitors when given testosterone therapy; however, this is controversial.

The primary complication of the surgical implantation is postoperative infection, which occurs in about 8% of cases involving diabetes. This infection can be difficult to treat and may require the removal of the device, although this occurs <3% of the time. The infection can also cause penile erosion, reduced penile sensation, and auto-inflation. Glycemic control should be optimized several weeks before surgery. Once a patient has surgery, none of the oral agents or vacuum devices will work because of the destroyed penile architecture.


But don’t panic. ED can be caused by a number of factors, from depression and medication side effects to high blood pressure, high cholesterol, low testosterone levels, Peyronie’s disease, nerve damage, performance anxiety, heart disease, diabetes, and more. Even better, many of these ED causes are treatable with medication and simple lifestyle changes. It’s important to know the root cause of your erectile dysfunction in order to treat it in the fastest, most effective way possible. Here are the 5 most common causes of erectile dysfunction.


Diabetes can cause nerve, blood vessel, and muscle damage that results in problems like pain, numbing or loss of sensation in the hands and feet.12 These issues can also result in ED problems, because nerve signals and blood flow are necessary to the process of getting an erection.6 And as men with diabetes get older, ED problems become even more common.13

It was recommended that the patient focus on relaxation techniques, increase cardiovascular exercise, take cialis 5 mg PO prn as it is effective, and to start scheduled terazosin 1 mg po at bedtime to relax the hypertonic cavernous smooth muscle. It was recommended that he utilize lubricants for masturbation, that he decrease the frequency of masturbation, and that he investigate vibrators to increase glanular stimulation if necessary. It was also recommended that he stop using the various alternative therapies that he has been using for the past 6 months (topicals, lasers, electromagnetic therapies, hyperbaric oxygen), which were likely confounding the issue. At follow up, 4 weeks after the initial visit, the patient reported 60% improvement in his symptoms with seldom use of PDE5 inhibitors.
Begot, I., Peixoto, T. C. A., Gonzaga, L. R. A., Bolzan, D. W., Papa, V., Carvalho, A. C. C., ... & Guizilini, S. (2015, March 1). A Home-Based Walking Program Improves Erectile Dysfunction in Men With an Acute Myocardial Infarction. The American Journal of Cardiology, 115(5), 5741-575. Retrieved from http://www.ajconline.org/article/S0002-9149(14)02270-X/abstract
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]
Alcohol abuse is the leading cause of impotence and other disturbances in sexual dysfunction.[3] Episodic erectile failure in alcoholic men is fairly routine, found to be significantly higher in men consuming more than three standard units of alcohol (12 g ethanol) daily and in subjects smoking more than 10 cigarettes/day.[4] Van Thiel and Lester[5] reported that 61% of patients dependent on alcohol reported sexual dysfunction, the most common being erectile dysfunction followed by reduced sexual desire. Erectile dysfunction and reduced sexual desire were frequently seen to be coexisting.[6–9] Vijayasenan,[10] found that of 97 male inpatients admitted for the treatment of alcoholism, 71% suffered from sexual dysfunction for a period of more than 12 months prior to admission to a hospital. The disturbances noted were diminished sexual desire (58%), ejaculatory incompetence (22%), erectile impotence (16%) and premature ejaculation (4%). Virtually all aspects of the human sexual response are affected by alcohol especially sexual desire and erection.[11]
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."
The improvement of both man and woman sexual function in couples whose male partner is treated with PDE5i has been further confirmed by randomized clinical trials (RCTs) comparing the effectiveness of PDE5i vs. placebo in improving couple sexual function (91-95). In a more recent RCT, the use of vardenafil 10 mg oral dispersible tablets has been compared to the use of the drug itself in association with cognitive behavioral sexual therapy (CBST) for 10 weeks in 30 couples with ED male partners, randomly assigned to one study arm (96). Results from this RCT showed that vardenafil is able to improve male sexual function, but this improvement is maintained only in patients receiving both vardenafil and CBST. Furthermore, female sexual function and satisfaction are enhanced only in the arm with vardenafil and CBST combined therapy, thus suggesting that a therapy healing the couple is more effective and has a longer-lasting efficacy than the use of a medication focusing only on ED.
Anxiety is the most common cause of erectile dysfunction in young men. This can include nervousness about getting your partner pregnant, losing your erection while putting a condom on, or your sexual performance. This often creates a negative spiral, because failure to achieve an erection causes yet more anxiety and stress. Depression, anxiety and stress can also cause ED by reducing libido.
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.
A daily glass of wine, beer or single malt over dinner or after work with your buddies will not lead to erectile dysfunction (ED), inability to get or maintain an erection during sex. Overindulging, though, will short-circuit your sex life. Besides waking up with a major hangover, overdoing it will eventually lead to hardening of the arteries and cardiovascular disease, which interferes with blood flow to your  equation is simple: the less blood flow, the soft and skimpier the erection. Unless you can drink in moderation, avoid alcohol if you want to be at your best in bed.
Condom troubles. Can the simple act of putting on a condom cause so much stress that it actually leads to erectile dysfunction? Sure it can — in fact, one recent survey of 234 young men conducted by the Children's Memorial Hospital in Chicago found that 25 percent had lost an erection while putting on a condom. “Putting on a condom requires a break from stimulation, and when it is on, it can reduce sensation,” says Dr. Montague.

Erections are neurovascular events, meaning that nerves and blood vessels (arteries and veins) are involved in the process of an erection and all must work properly to develop a hard erection that lasts long enough. Erection begins with sexual stimulation. Sexual stimulation can be tactile (for example, by a partner touching the penis or by masturbation) or mental (for example, by having sexual fantasies, viewing porn). Sexual stimulation or sexual arousal causes the nerves going to the penis to release a chemical, nitric oxide. Nitric oxide increases the production of another chemical, cyclic GMP (cGMP), in the muscle of the corpora cavernosa. The cGMP causes the muscles of the corpora cavernosa to relax, and this allows more blood to flow into the penis. The incoming blood fills the corpora cavernosa, making the penis expand.
These are among the most challenging patients seen in urology practice today: a young, healthy man with neither systemic disease nor a history of trauma, who has complaints of ED (Table 2). These men often have co-morbid diagnoses, such as anxiety, depression, or mood disorders, which make the issue of ED more complex for both the patient and the urologist (12). The psychological burden of ED in these young men is more pronounced than it might be in older men as this is the phase of life during which many men expect to be highly sexually active (4). These young men are usually technologically savvy and may have scrutinized much of the readily available information on the internet regarding ED. Often they arrive to clinic armed with an understanding of the diagnostic evaluation that may be offered to further investigate the etiology of their concerns. This makes the evaluation and treatment of these men more challenging since additional diagnostic testing is often not indicated after a thorough history and physical examination. In many cases, they may have self-diagnosed and self-treated based on the information that they obtained prior to seeing a physician. Many of these men will see multiple urologists on their quest to find a pathophysiology that they can accept, and many have unrealistic expectations of a rapid cure or a surgical cure.
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.

Smoking.   Smoking and erectile dysfunction are related as smoking leads to plaque build up in the arteries called cardiovascular disease, which restricts blood flow through the veins.  Arterial sclerosis from smoking restricts blood flow, and thus can prevent the massive amount of blood required for you to achieve an eretion, resulting in erectile dysfunction.
Erectile Dysfunction is not the same condition as premature ejaculation.  Men with premature ejaculation are able to achieve an erection sufficient for sexual intercourse, but due to over stimulation of the penis, ejaculate within one to two minutes of beginning intercourse with their partner.  Men with erectile dysfunction, on the other hand,  are unable to achieve hard erections capable of vaginal penetration or are not able to achieve an erection at all.
Getting blood glucose under control is a good anti-ED tactic. Men with diabetes and poor blood glucose control are two to five times as likely to have ED as those with good control. One study in a group of men who had had type 1 diabetes for up to 15 years with minor complications found that intensive blood glucose control lowered the risk of ED compared with conventional treatment. A study in men with type 2 diabetes found that lowering A1C (average blood glucose in the past two to three months) below 7 percent and reducing blood pressure through a combination of medication, diet, and exercise improved sexual functioning.
It’s important to make mention that ED can be associated with stress, hormones, emotional well-being, the nervous system, muscle tone, circulation, medications, and more. While there may be a simple explanation for the inability to maintain an erection, sexual arousal is a complex function of the body, so it’s in your best interest to consult with your doctor if you’re regularly having trouble sustaining an erection and having pleasurable sex.
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 is more common than most people think. About 40% of men will notice some degree of problem by age 40. The aging of the penis can begin as early as the late 20s but becomes severe enough to notice typically starting in the 40s. As men get older, their odds of getting erectile dysfunction increases by about 10% per decade, and the severity of the problem also increases.
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.

Not enough info for you? No problem. Nerd out on all the causes of erectile dysfunction with research from the most trusted sources on the interwebs. If you have any questions or you think we missed something important, leave a comment or book a consultation with one of these trained professionals and we’ll get you on the way to a healthier manhood.
It would be convenient if a fairy dickmother flew from the sky and told you this would be the drink that renders you flaccid, but when it comes to figuring out your limit, you’re on your own. There’s no hard and fast rule as to how much will actually affect you, either; Dr Mills notes that some men may be able to drink a lot and get erections, as everybody’s threshold is different.
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
Sexual dysfunction was rated for the last one year and temporary or situational complaints were ignored. Data regarding the quantity of alcohol usually consumed per day [in standard drinks; where 1 drink = 30 ml. Spirits = 330 ml. Beer = 1/3 sachet of arrack] and duration of dependence, was extracted from the items corresponding to the section on Mental and Behavioural disorders due to use of alcohol [F10.0] in the SCAN and used in the analyses. However, only the presence or absence of tobacco consumption and not a measure of severity was used for analyses. The ratings were sought after two weeks of inpatient stay after the period of detoxification with benzodiazepines.

Khoo, J., Piantadosi, C., Duncan, R., Worthley, S. G., Jenkins, A., Noakes, M., … Wittert, G. A. (2011, October). Comparing effects of a low-energy diet and a high-protein low-fat diet on sexual and endothelial function, urinary tract symptoms, and inflammation in obese diabetic men [Abstract]. The Journal of Sexual Medicine, 8(10), 2868-75. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/21819545
Depression. The profound sadness, emptiness, and hopelessness that characterize depression may also cause ED among younger men. “The biggest effect of depression is on a man’s desire for sexual relations, or libido,” says Drogo Montague, MD, director of the Center for Genitourinary Reconstruction in the Glickman Urological and Kidney Institute at the Cleveland Clinic. “To some extent, depression can affect a man’s ability to maintain an erection. It can be a chicken-and-egg situation. However, reduced libido is a common indicator of depression.”
Occasional difficulties in bed do not constitute ED – it is the persistent and consistent inability to maintain an erection through satisfactory intercourse. It is more common than men might think, given that they are loath to discuss it with others, often even their doctors. The condition has many causes and, as a result, affects men of all ages – though it becomes increasingly prevalent with age.
Pelvic exercises, commonly known as Kegel exercises, were first described in 1948 by American gynaecologist Arnold Kegel. They are usually advocated by doctors to women after they have delivered a baby, and are not something most men are aware of. But Kegels help promote urinary continence and sexual health because they strengthen the bulbocavernosus muscle, which does three things: allows the penis to engorge with blood during erection, pumps during ejaculation, and helps empty the urethra after urination.
Erectile dysfunction is more common than most people think. About 40% of men will notice some degree of problem by age 40. The aging of the penis can begin as early as the late 20s but becomes severe enough to notice typically starting in the 40s. As men get older, their odds of getting erectile dysfunction increases by about 10% per decade, and the severity of the problem also increases.

What has been excluded entirely from all recent discussions of ED in young men is a concept presented many years ago—the concept of increased sympathetic tone as an organic etiology of “psychogenic” erectile dysfunction in young men (5). Previous studies have shown that elevated central sympathetic tone may be one cause of impotence (6,7). This article focuses on the presentation, work-up, and treatment of young men (age: 16–35 years old) with complaints of ED, and we will attempt to present a new method of approaching these patients. It is important to identify the precise etiology of ED in these men before proceeding with potentially unnecessary evaluation and treatment as the process can be anxiety-provoking, invasive, and costly and may provide an unreliable diagnosis which produces further psychological distress in these psychologically fragile young men.
Neurologic illnesses leading to ED have been recently reviewed (64). The most common of them (i.e., consequences of prostatic surgery, stroke and Parkinson’s disease) are not typical of younger age and, similarly to conditions less common but more typical of younger men, such as spinal cord injury, multiple sclerosis and spina bifida, the clinical features of the underlying disease are clearly apparent, being ED one of the multiple manifestations, rather than a harbinger of a subtle condition. Diagnosis of neurologic origin of ED is often quite simple, based on medical history and physical exam. The clinical management is a multidimensional and coordinated work of rehabilitation and medical therapy, which includes ICI injection of vaso-relaxant drugs, vacuum device and surgery (64).
There have been rare reports of priapism (prolonged and painful erections lasting more than six hours) with the use of PDE5 inhibitors such as sildenafil, vardenafil, and tadalafil. Patients with blood cell diseases such as sickle cell anemia, leukemia, and multiple myeloma have higher than normal risks of developing priapism. Untreated priapism can cause injury to the penis and lead to permanent impotence. Therefore, if your erection lasts four hours, you should seek emergency medical care.

Certain feelings can interfere with normal sexual function, including feeling nervous about or self-conscious about sex, feeling stressed either at home or at work, or feeling troubled in your current sexual relationship. In these cases, treatment incorporating psychological counseling with you and your sexual partner may be successful. One episode of failure, regardless of cause, may propagate further psychological distress, leading to further erectile failure. Los of desire or interest in sexual activity can be psychological or due to low testosterone levels.


A 2013 study published in The Journal of Sexual Medicine evaluated 439 men for erectile dysfunction and compared ED causes and frequency in men 40 or younger to men over 40. They found that 26 percent of the younger men had ED. Although these men were healthier and had higher levels of testosterone than the older men, they were more likely to be smokers or to have used illicit drugs. In almost half of the younger men with ED, the ED was considered severe.
A medical history focused on risk factors, such as cigarette smoking, hypertension, alcoholism, drug abuse, trauma, and endocrine problems including hypothyroidism, low testosterone levels, and hyperprolactinemia, is very important. Commonly used drugs that disrupt male sexual function are spironolactone (Aldactone), sympathetic blockers such as clonidine (Catapres), guanethidine (Islemin), methyldopa (Aldomet), thiazide diuretics, most antidepressants, ketoconazole (Nizoral), cimetidine (Tagamet), alcohol, methadone, heroin, and cocaine. Finally, assessment of psychiatric history will help identify emotional issues such as interpersonal conflict, performance anxiety, depression, or anxiety.

It's not easy to get in the mood when you're overwhelmed by responsibilities at work and home. Stress can take its toll on many different parts of your body, including your penis. Deal with stress by making lifestyle changes that promote well-being and relaxation, such as exercising regularly, getting enough sleep, and seeking professional help when appropriate.
ED usually has something physical behind it, particularly in older men. But psychological factors can be a factor in many cases of ED. Experts say stress, depression, poor self-esteem, and performance anxiety can short-circuit the process that leads to an erection. These factors can also make the problem worse in men whose ED stems from something physical.

The medications are extremely effective, which is very good. And the medications are, for the most part, extremely well-tolerated. But there are, like with any medications, a potential downside. The one absolute downside to the use of any of these erection what we call PDE5 medications is if a patient is using a nitroglycerin medication. And nitroglycerins are used for heart disease and for angina, for the most part, although there are some recreational uses of nitrites. And that’s important because your blood vessels will dilate and your blood pressure will drop. And that is an absolute contraindication.
To give you some evidence of the link between anxiety, stress, and ED consider the results of a study published in a 2015 edition of Comprehensive Psychiatry. In a study of case records for 64 men with erectile dysfunction or premature ejaculation, there was a significant link between ED and anxiety disorders or depression. Of the 64 participants, 8 had comorbid depressive disorders and 15 had anxiety disorders. In the majority of patients, these disorders predated the onset of sexual dysfunction which suggests that the disorders may have been a contributing factor.
Men with a rare heart condition known as long QT syndrome should not take vardenafil since this may lead to abnormal heart rhythms. The QT interval is the time it takes for the heart's muscle to recover after it has contracted. An electrocardiogram (EKG) measures the QT interval. Some people have longer than normal QT intervals, and they may develop potentially life-threatening abnormal heart rhythms, especially when given certain medications. Men with a family history of long QT syndrome should not take vardenafil, as it is possible to inherit long QT syndrome. Furthermore, vardenafil is not recommended for men who are taking medications that can affect the QT interval such as quinidine (Quinaglute, Quinidex), procainamide (Pronestyl, Procan-SR, Procanbid), amiodarone (Cordarone), and sotalol (Betapace).

Quitting smoking, exercising regularly, losing excess weight, curtailing excessive alcohol consumption, controlling hypertension, and optimizing blood glucose levels in patients with diabetes are not only important for maintaining good health but also may improve or even prevent progression of erectile dysfunction. It is unclear if such lifestyle changes can reverse erectile dysfunction. However, lifestyle improvements may prevent progression of the erectile dysfunction. Some studies suggest that men who have made lifestyle improvements experience increased rates of success with oral medications.
This man’s situational ED, possibly due to performance anxiety or perhaps fear of a repeat injury and pain. Structural, neurogenic, arteriogenic, and venous occlusive erectile dysfunction can be ruled out as he has normal self-stimulated erections. He responds well to low dose oral PDE5 inhibitors. Additional assessment with cold and hot perception testing and biothesiometer were performed due to his complaint of decreased sensation; both test results were normal. He was started on low dose terazosin once daily at bedtime along with Cialis 5 mg as needed. He is responding well to treatment.
To understand what happens in ED, it's helpful to know some anatomical basics. When aroused by either sensory or mental stimuli, the brain sends a signal through the nerves to the penis, causing the muscles there to relax. This opens up space for blood to flow in and engorge the penis. A membrane within the penis traps blood inside to help maintain the erection, which subsides when the penile muscles contract, forcing blood back into the rest of the body. Any number of things can go wrong in this process, leading to erectile dysfunction.
A vacuum erection device is a plastic tube that slips over the penis, making a seal with the skin of the body. A pump at the other end of the tube makes a low-pressure vacuum around the erectile tissue, which results in an erection. An elastic ring is then slipped onto the base of the penis. This holds the blood in the penis (and keeps it hard) for up to 30 minutes. With proper training, 75 out of 100 men can get a working erection using a vacuum erection device.
With coronary artery disease, a buildup of plaque inside the arteries can limit the amount of blood that’s able to flow through them. If the flow of oxygen-rich blood to your heart muscle is reduced or blocked by this hardening of the arteries, the result can be angina (chest pain) or a heart attack.17 Because the arteries that supply blood to the penis are much smaller than the ones that feed the heart, the problem may show up earlier as having difficulty getting an erection.18
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.
The initial step in evaluating ED is a thorough sexual history and physical exam. The history can help in distinguishing between the primary and psychogenic causes. It is important to explore the onset, progression, and duration of the problem. If a man gives a history of “no sexual problems until one night,” the problem is most likely related to performance anxiety, disaffection, or an emotional problem. Aside from these causes, only radical prostatectomy or other overt genital tract trauma causes a sudden loss of male sexual function.
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