Vardenafil and tadalafil belong to the same group of chemical compounds as sildenafil, namely phos-phodiesterase type 5 (PDE-5) inhibitors. Some men cannot benefit from sildenafil or the two newer PDE-5 inhibitors because they have low levels of nitric oxide. British investigators reported in late 2002 that three different types of compounds are being studied as possible medications for men with low levels of nitric oxide. They are Rho-kinase inhibitors, soluble guanylate cyclase activators, and nitric oxide-releasing PDE-5 inhibitors.


Depression and anxiety: Psychological factors may be responsible for erectile dysfunction. These factors include stress, anxiety, guilt, depression, widower syndrome, low self-esteem, posttraumatic stress disorder, and fear of sexual failure (performance anxiety). It is also worth noting that many medications used for treatment of depression and other psychiatric disorders may cause erectile dysfunction or ejaculatory problems.
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.

Conditions associated with reduced nerve and endothelium function (eg, aging, hypertension, smoking, hypercholesterolemia, and diabetes) alter the balance between contraction and relaxation factors (see Pathophysiology). These conditions cause circulatory and structural changes in penile tissues, resulting in arterial insufficiency and defective smooth muscle relaxation. In some patients, sexual dysfunction may be the presenting symptom of these disorders.

Penile prostheses are very effective, and most patients who have a prosthesis placed are satisfied with the prosthesis. However, placement of a prosthesis causes scarring of the tissue within the corpora cavernosa, and if the prosthesis requires removal, other forms of therapy, except for the vacuum device, are often not effective. Thus, most physicians reserve placement of a prosthesis for men who have tried and failed or have contraindications to other therapies.
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.
Stiffy Solution: The good news is, almost all of these conditions can be successfully treated if you catch them early on. And since erectile problems may be the first side effect your dude has experienced, seeking medical treatment for his erectile problems may be the thing to get him into a doctor's office. So if your dude is a well-rested, non-drinking, non-smoking, paragon of relaxation who suddenly can't get wood, urge him to talk to his doctor — his misbehaving penis may actually be communicating something way more important than "Not tonight, honey."
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
Your erection problems may be putting a strain on your relationship. You may have stopped touching and cuddling your partner, scared that it could lead to sex - and then to disappointment because you cannot get hard. You may have found it has led to regular arguments. At its worst, erection problems can lead to the breakdown of relationships. So it is vitally important to talk things over with your partner.
An approach to the diagnosis and management of the impotent patient is presented in Figure 187.1. Apparent and likely causes of impotence should be considered first and, if possible, eliminated before the work-up continues. For instance, observing the patient for a few weeks off offending medication may be all that is necessary to establish the cause of impotence. When no obvious or remediable cause is present, the next step is based on the clinical impression of the likelihood of organic versus psychologic impotence. If the latter is considered more likely, it is perfectly reasonable to refer the patient directly for sexual therapy, with the option of reconsidering the diagnosis if, after appropriate therapy, there is no improvement. While an occasional patient with organic impotence will be misrouted, many more with psychogenic impotence will be spared an unnecessary and costly evaluation for organic causes. When organic impotence is likely, a serum testosterone level is the initial screening test for hypogonadism and should be obtained prior to urologic referral. Patients with low testosterone levels require further endocrine evaluations as depicted in Figure 187.1.

One study examined the role of testosterone supplementation in hypogonadal men with ED. These men were considered nonresponders to sildenafil, and their erections were monitored by assessing nocturnal penile tumescence (NPT). After these men were given testosterone transdermally for 6 months, the number of NPTs increased, as did the maximum rigidity with sildenafil. [18] This study suggests that a certain level of testosterone may be necessary for PDE5 inhibitors to function properly.
If you have been having ED for more than two months, you should see a doctor to find the cause. To detect the cause of ED, your doctor will take a history of when you started to have problems with erections and sex drive, illnesses or injuries that could cause ED, and any recent physical or emotional changes in your life. You also will need to review all the medications you take. The evaluation most often includes a physical exam.
The user should stop using the vacuum pump if pain occurs... Use of a vacuum pump may bruise or rupture the blood vessels either immediately below the surface of the skin or within the deep structures of the penis or scrotum, resulting in hemorrhage and/or the formation of a hematoma. There is now sufficient information available regarding the risks, benefits, and use of vacuum pumps.
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.
Sexual dysfunction is highly prevalent in men and women. In the MMAS, 52% of the respondents reported some degree of erectile difficulty. Complete ED, defined as (1) the total inability to obtain or maintain an erection during sexual stimulation and (2) the absence of nocturnal erections, occurred in 10% of the respondents. Mild and moderate ED occurred in 17% and 25% of responders, respectively. [15]
To examine what is known about the demographics, etiology, risk factors, pathophysiology, diagnostic assessment, treatments (both generic and cause-specific), and the understanding of their consequences by the public and the medical community, the National Institute of Diabetes and Digestive and Kidney Diseases and the Office of Medical Applications of Research of the National Institutes of Health, in conjunction with the National Institute of Neurological Disorders and Stroke and the National Institute on Aging, convened a consensus development conference on male impotence on December 7-9, 1992. After 1 1/2 days of presentations by experts in the relevant fields involved with male sexual dysfunction and erectile impotence or dysfunction, a consensus panel comprised of representatives from urology, geriatrics, medicine, endocrinology, psychiatry, psychology, nursing, epidemiology, biostatistics, basic sciences, and the public considered the evidence and developed answers to the questions that follow.
To reach the largest audience, communications strategies should include informative and accurate newspaper and magazine articles, radio and television programs, as well as special educational programs in senior centers. Resources for accurate information regarding diagnosis and treatment options also should include doctors' offices, unions, fraternal and service groups, voluntary health organizations, State and local health departments, and appropriate advocacy groups. Additionally, since sex education courses in schools uniformly address erectile function, the concept of erectile dysfunction can easily be communicated in these forums as well.
Psychosocial problems are important and may cause erectile dysfunction by themselves or together with other causes of erectile dysfunction, such as diabetes and heart disease. Relationships are complicated and many factors cause tensions, which can affect sexual relations. For some men, these problems can become ongoing and it can help to talk through the issue with a skilled counsellor. It is important to know that the longer erectile dysfunction is left untreated, the greater the effect on relationships. This is another reason why early treatment of erectile dysfunction is important.
Let’s admit that not “talking about anything that could possibly be uncomfortable” is a sure-fire recipe for total disaster. Maybe you’re exaggerating, but if he can’t deal with anything even slightly difficult, then that is a bigger problem than pillow talk. Think about how exactly it would affect everything else in your relationship. He can’t choose not to deal. When good things are happening, it’s a shame he can’t say "I love you0". But when hard things happen, he can’t just say: "Um, pass."
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."

Men with physical causes of ED have options, including such medicines as sildenafil (Viagra®), vardenafil (Levitra®), or tadalafil (Cialis®). Men who use nitroglycerin products and those who should avoid sexual activity because of cardiovascular disease shouldn’t take these drugs. Other treatment modalities include use of a vacuum pump or injection of a substance (papaverine) into the penis to increase blood flow to the penis. Men can also have surgery to put a prosthesis into the penis.


Psychosexual counselling, or sex therapy, is an appropriate recommendation especially for men who are experiencing discord with their partner especially if the conflict is related to the man’s ED. Counselling usually consists of 5–20 sessions with counsellor. It is our recommendation that referral doctors treating men with ED make a referral to a psychotherapist or sex therapist who is certified by AASECT (American Association of Sexuality Educators, Counselors and Therapists) of certified sexuality educator.43
…have traditionally been classified as impotence (inability of a man to achieve or maintain penile erection) and frigidity (inability of a woman to achieve arousal or orgasm during sexual intercourse). Because these terms—impotence and frigidity—have developed pejorative and misleading connotations, they are no longer used as scientific classifications, having been…

In patients who either fail to respond to first or second-line therapy, or are not interested in the conservative therapies, penile prosthesis implantation is available. Malleable and rigid implants were available for many years, but in 1973 the world of penile prosthetics took a giant leap forward with the advent of the inflatable penile implant. Most implants done nowadays are of the inflatable variety. Adverse events including malfunction and infection are rare, and patient satisfaction is very high.45
Patients should continue testosterone therapy only if there is improvement in the symptoms of hypogonadism and should be monitored regularly. You will need periodic blood tests for testosterone levels and blood tests to monitor your blood count and PSA. Testosterone therapy has health risks, and thus doctors should closely monitor its use. Testosterone therapy can worsen sleep apnea and congestive heart failure.
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.
Sexual dysfunction is highly prevalent in men and women. In the MMAS, 52% of the respondents reported some degree of erectile difficulty. Complete ED, defined as (1) the total inability to obtain or maintain an erection during sexual stimulation and (2) the absence of nocturnal erections, occurred in 10% of the respondents. Mild and moderate ED occurred in 17% and 25% of responders, respectively. [15]
#2 Physically exhausted. If you’ve been cranking it at the gym, haven’t been sleeping well, or you’ve been working your ass off at your job, getting tangled up with your lover for even more physically demanding activities may not sound ideal. Physical exhaustion has a direct effect on your ability to get aroused. The only fix for this one is to get some rest.
For some patients with an established diagnosis of testicular failure (hypogonadism), androgen replacement therapy may sometimes be effective in improving erectile function. A trial of androgen replacement may be worthwhile in men with low serum testosterone levels if there are no other contraindications. In contrast, for men who have normal testosterone levels, androgen therapy is inappropriate and may carry significant health risks, especially in the situation of unrecognized prostate cancer. If androgen therapy is indicated, it should be given in the form of intramuscular injections of testosterone enanthate or cypionate. Oral androgens, as currently available, are not indicated. For men with hyperprolactinemia, bromocriptine therapy often is effective in normalizing the prolactin level and improving sexual function. A wide variety of other substances taken either orally or topically have been suggested to be effective in treating erectile dysfunction. Most of these have not been subjected to rigorous clinical studies and are not approved for this use by the Food and Drug Administration (FDA). Their use should therefore be discouraged until further evidence in support of their efficacy and indicative of their safety is available.
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.
Davis Liu, MD is a board certified family physician, patient advocate, physician leader, blogger, and the author of two books, including The Thrifty Patient – Vital Insider Tips for Saving Money and Staying Healthy. He’s passionate about making healthcare more convenient, personalized, and affordable. Prior to joining, Dr. Liu was a practicing primary-care doctor for fifteen years at Kaiser Permanente in Roseville, California. He also served on the Permanente Medical Group (TPMG) Board of Directors as Vice Chair of the Finance and Audit committee and the Governance committee. Dr. Liu graduated summa cum laude and Phi Beta Kappa from the Wharton School of Business at the University of Pennsylvania. He received his medical degree from the University of Connecticut School of Medicine.
Patient can inject medications directly into the corpora cavernosa to help attain and maintain erections. Medications such as papaverine hydrochloride, phentolamine, and prostaglandin E1 (alprostadil) can be used alone or in combinations to attain erections. All of these medications are vasodilators and work by increasing blood flow into the penis. Prostaglandin E1 (Caverject, Edex) is easier to obtain; however, it is associated with penile pain in some individuals. The use of combinations of two or three of these medications can decrease the risk of having penile pain.

Sildenafil (Viagra) was the first oral phosphodiesterase type 5 (PDE5) inhibitor approved by the FDA in the United States for the treatment of erectile dysfunction (it is not approved for women). Sildenafil inhibits PDE5, which is an enzyme that destroys cGMP. By inhibiting the destruction of cGMP by PDE5, sildenafil allows cGMP to accumulate. The cGMP in turn prolongs relaxation of the smooth muscle of the corpora cavernosa. Relaxation of the corpora cavernosa smooth muscle allows blood to flow into the penis resulting in increased engorgement of the penis. In short, sildenafil increases blood flow into the penis and decreases blood flow out of the penis.


Yohimbine: The main component of an African tree bark, yohimbine is probably one of the most problematic of all natural remedies for ED. Some research suggests that yohimbine can improve a type of sexual dysfunction that is linked with a drug used to treat depression. However, studies have linked yohimbine to a number of side effects, which can include anxiety, increased blood pressure, and a fast, irregular heartbeat. Like all natural remedies, yohimbine should only be used after advice and under supervision from a doctor.
The information shared on our websites is information developed solely from internal experts on the subject matter, including medical advisory boards, who have developed guidelines for our patient content. This material does not constitute medical advice. It is intended for informational purposes only. No one associated with the National Kidney Foundation will answer medical questions via e-mail. Please consult a physician for specific treatment recommendations.
The appropriate evaluation of all men with erectile dysfunction should include a medical and detailed sexual history (including practices and techniques), a physical examination, a psycho-social evaluation, and basic laboratory studies. When available, a multidisciplinary approach to this evaluation may be desirable. In selected patients, further physiologic or invasive studies may be indicated. A sensitive sexual history, including expectations and motivations, should be obtained from the patient (and sexual partner whenever possible) in an interview conducted by an interested physician or another specially trained professional. A written patient questionnaire may be helpful but is not a substitute for the interview. The sexual history is needed to accurately define the patient's specific complaint and to distinguish between true erectile dysfunction, changes in sexual desire, and orgasmic or ejaculatory disturbances. The patient should be asked specifically about perceptions of his erectile dysfunction, including the nature of onset, frequency, quality, and duration of erections; the presence of nocturnal or morning erections; and his ability to achieve sexual satisfaction. Psychosocial factors related to erectile dysfunction should be probed, including specific situational circumstances, performance anxiety, the nature of sexual relationships, details of current sexual techniques, expectations, motivation for treatment, and the presence of specific discord in the patient's relationship with his sexual partner. The sexual partner's own expectations and perceptions should also be sought since they may have important bearing on diagnosis and treatment recommendations.

Watts and coworkers, in their review article, make several points about this ED/CAD nexus. Endothelial dysfunction is present in both CVD and ED, and is linked through the NO mechanism. The authors note that PDE5 inhibitors improve endothelial function and have a salutary effect on both CVD and ED. Both ED and cardiac disease respond to modifications in lifestyle as well as pharmacologic manipulation. These authors also report that the presence of ED gives the clinician an opportunity to assess CVD and prevention as well.20
Most bouts of ED can be explained away by stress, anxiety, or nervousness. If erectile dysfunction becomes frequent, don’t panic, but cover your bases by seeing a doctor to rule out scarier causes like diabetes or prostate cancer. Medications like antidepressants can also cause boner loss. Unless you can’t get it up after a date because you spent the day snorting coke and fucking your ex (in which case figure some shit out before you see other people) this line places the blame on the stress of work and away from your partner. While a woman will usually be understanding, she may fear you can’t get hard because you’re not attracted to her. Ease these anxieties with this line. Even if work was great and you’re having trouble getting it up because of other stress, like a text from an ex or family shit you’re not ready to disclose, I’ll allow a little white lie in this instance.
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Diabetes is one of the most common causes of ED. Chronically high blood sugar levels can result in nerve damage that affects your body’s ability to translate pleasurable sexual stimulation into an erection. Diabetes can also lead to issues with circulation, which reduces blood flow to the penis and makes it more difficult to keep an erection that is hard enough for intercourse.
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