Normal male sexual function requires a complex interaction of vascular, neurological, hormonal, and psychological systems. The initial obligatory event is acquisition and maintenance of an erect penis, which is a vascular phenomenon. Normal erections require blood flow into the corpora cavernosae and corpus spongiosum. As the blood accelerates, the pressure within the intracavernosal space increases dramatically to choke off penile venous outflow. This combination of increased intracavernosal blood flow and reduced venous outflow allows a man to acquire and maintain a firm erection.

Feeling fatigued, very stressed, depressed or dealing with another mood-related issue that can lower libido. Sources of stress and diminished quality of life — such as “deteriorating economic position,” unhappiness with one’s job or other aspects that lower emotional health — are believed to be major causes for sexual dysfunction in both men and women
A number of drugs are known to cause ED in patients with DM (Table 1). For example, many EDDM patients are on antihypertensive medications. Replacement of thiazides or beta-blockers with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers may be sufficient to regain erectile ability.5 Furthermore, discontinuation of selective serotonin reuptake inhibitors, if these drugs are not essential for patient well-being, may be therapeutic. Careful monitoring following drug discontinuation will help to determine if ED is due to the medication or other underlying disorders. The benefits of continued drug therapy with these drugs should always be weighed against the likelihood of causing ED and impacting on the patient's QOL.
A penile prosthesis is another treatment option for men with erectile dysfunction. These devices are either malleable (bendable) or inflatable. The simplest type of prosthesis consists of a pair of malleable rods surgically implanted within the erection chambers of the penis. With this type of implant the penis is always semi-rigid and merely needs to be lifted or adjusted into the erect position to initiate sex. Today, many men choose a hydraulic, inflatable prosthesis, which allows a man to have an erection whenever he chooses and is much easier to conceal. It is also more natural.
Intraurethral alprostadil (Muse) provides a less invasive alternative to intrapenile injection. It is a pellet that is inserted 5–10 min before intercourse, and its effects last for 1 h. The response rate is ∼50–60%. It can be used twice daily but is not recommended for use with pregnant partners. Complications of priapism and penile fibrosis are less common than after alprostadil given by penile injection. The cost is ∼$18–24 per treatment.

Despite its limitations in detecting CVD without significant stenosis, EST (with or without imaging) can further define the cardiovascular risk in patients with ED and no overt CAD and may be particularly helpful for identifying silent CAD in patients with diabetes. Chemical stress tests are appropriate for patients who cannot complete an EST or in whom ECG is non-interpretable. In patients with established CVD, an interpretable EST is mandatory in the indeterminate risk category and is at the discretion of the cardiologist in the low risk category (Table 3B), since it determines exercise ability and estimates cardiovascular risk associated with sexual activity.

However, sildenafil should be used carefully with nitrates because their combination can result in severe hypotension and death.68 Both short- and long-acting nitrates are commonly prescribed to treat angina, but they have no prognostic benefit. In addition, there are numerous alternatives to treat angina, such as ranolazine and ivabradine, which do not interact with PDE5 inhibitors. As a result, patients with ED wishing to take PDE5 inhibitors can safely discontinue their nitrates and replace this treatment with the other anti-anginal agents.68
Physical and sexual activity can trigger acute cardiac events. In a recent meta-analysis, a significant association between acute cardiac events and episodic physical (relative risk 3.45 for myocardial infarction and 4.98 for sudden cardiac death) and sexual activity (relative risk 2.7 for myocardial infarction) was demonstrated.32 This association was attenuated among individuals with high levels of habitual physical activity (for every additional time per week the relative risk for myocardial infarction decreased by ∼45%, and the relative risk for sudden cardiac death decreased by 30%). The physical demands of sexual activity have been identified as follows. Studies conducted primarily in young married men showed that sexual activity with a person's usual partner is comparable with mild-to-moderate physical activity in the range of 3–4 metabolic equivalents of the task (METS).30,33 The heart rate rarely exceeds 130 b.p.m. and systolic blood pressure rarely exceeds 170 mmHg in normotensive individuals. Accordingly, demands during sexual activity correspond to walking 1.5 km (or 1 mile) on the flat in 20 min or briskly climbing two flights of stairs in 10 s. Generalization, however, may not characterize all individuals (especially those who are older, are less physically fit, or have CVD) or sexual activity circumstances (e.g. extramarital, unfamiliar setting, excessive food and alcohol consumption). Therefore, completing 4 min of the standard Bruce treadmill protocol (5–6 METS) without symptoms, ST segment changes, arrhythmias, or a fall in systolic BP identifies the safety of sexual activity.30,33

In Eastern medicine, animal products are commonly used for their perceived health benefits. The philosophy “like nourishes like”, suggests that consuming the organ of an animal will bring benefits to the corresponding organ in one’s body is a common belief. Men seeking greater potency have turned to eating penises from goats, bull, deer, horses, seals and other mammals in the form of cooked dishes or herbal preparations. While there is no scientific evidence supporting this practice, the cultural beliefs remain strong and supplements containing extracts from animal penises are readily available in the form of capsules, often mixed with herbal compounds pitching similar erectogenic properties. A significant proportion of these potency-inducing supplements in Asia have been found to contain PDE5-inhibitors substrates such as tadalafil and sildenafil (30). However uncontrolled use of illicit PDE5-inhibitors under the guise of natural supplements remains a health threat to the general public.


Branded Viagra can now be bought over the counter in pharmacies, but please check with your GP first if you have a medical condition. It's important to use a reputable pharmacy, as there is a large market in counterfeit drugs for erectile dysfunction, especially over the internet. These contain varying amounts of the active ingredient and sometimes completely different drugs.
A deficiency of L-arginine, however, does not generally disrupt nitric oxide synthesis because L-arginine availability is not the rate-limiting step in this process. In fact, research over the past five years has identified an endogenous (occurs in the body naturally) inhibitor called “asymmetric dimethylarginine” or ADMA, an amino acid which blocks the production of nitric oxide. By acting as an L-arginine mimic, this damaging look-alike effectively elbows out L-arginine and pushes it off to the side in the biochemical pathway leading to the synthesis of nitric oxide. ADMA is relatively elevated in patients with hypertension, high levels of cholesterol, triglycerides, homocysteine and low-density lipoprotein (LDL), and low levels of high-density lipoprotein (HDL), as well as with aging itself. This inhibitor of nitric oxide synthesis may very well be the common factor shared by all of these abnormal conditions. Increased levels of this detrimental inhibitor (ADMA) block nitric oxide production, leading to endothelial dysfunction.
Olsson et al. conducted a randomised, double-blind, placebo-controlled, parallel group, and flexible dose study in 224 men with ED and one CVD, including IHD (20 %) and hypertension (80 %). This study reported that the sildenafil-treated group showed 71 % improvement in ED compared with the placebo-controlled group (24 %).64 Furthermore, no treatment-related cardiovascular adverse events were reported.65 Conti et al. showed in an early study that sildenafil is an effective treatment for ED in patients with IHD; the majority of patients reported improvement in penile erection with it.66 Another double-blind, placebo-controlled study of patients with ED and stable CAD showed statistically significant improvement with sildenafil versus placebo in both the frequency of penetration and frequency of maintained erections after penetration.67

The causes of ED are numerous but generally fall into two categories: organic or psychogenic. The organic causes can be subdivied into five categories: vascular, traumatic/postsurgical, neurological, endocrine-induced, and drug-induced. Examples of the psychogenic causes are depression, performance anxiety, and relationship problems. In people with diabetes, the main risk factors are neuropathy, vascular insufficiency, poor glycemic control, hypertension, low testosterone levels, and possibly a history of smoking.
Cigarette smoking is an established risk factor in the development of atherosclerotic vascular changes and thus would be expected to play a role in the development of vasculogenic ED. The MMAS 9-year follow-up study found that the risk of developing moderate or complete ED in smokers was nearly doubled (odds ratio, 1.97) compared with that in matched nonsmokers.5x5Feldman, HA, Johannes, CB, Derby, CA et al. Erectile dysfunction and coronary risk factors: prospective results from the Massachusetts Male Aging Study. Prev Med. 2000; 30: 328–338
You may reduce your risk of ED by improving your heart health. Healthy lifestyle choices often encourage you to stop smoking, lose weight and increase physical activity. If ED persists, oral medications are a common first therapy for ED. If oral medications don’t work for you, the penile implant may be an option. The implant is concealed inside the body. It offers support for an erection whenever and wherever desired.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (53) | Google ScholarSee all References Coital position has not been shown to play a role in increased cardiovascular risk; similar peak heart rates and blood pressure levels are evident with either the man or the woman in the superior position during intercourse.90x90Nemec, ED, Mansfield, L, and Kennedy, JW. Heart rate and blood pressure responses during sexual activity in normal males. Am Heart J. 1976; 92: 274–277
According to the Mayo Clinic, oral medications are usually the first-line treatment for ED. Those medications include Sildenafil (Viagra), vardenafil (Levitra, Staxyn), tadalafil (Cialis) and avanafil (Stendra). They operate by helping relax muscles in the penis by strengthening the effects of nitric oxide, a naturally occurring chemical in the body. The drugs increase blood flow to allow patients to get an erection.

Viagra, Cialis, Levita, and Staxyn all work in a similar fashion and make it physically possible to get an erection when aroused. However, men whose blood pressure is poorly controlled and who take alpha-blockers for high blood pressure treatment should not take any of these treatments for erectile dysfunction as it may reduce blood pressure to critically low levels, causing fainting or sudden death. Also, you may be prohibited to use these drugs if you demonstrate any of the following:


Men with diabetes tend to develop erectile dysfunction 10 to 15 years earlier than men without diabetes. As men with diabetes age, erectile dysfunction becomes even more common. Above the age of 50, the likelihood of having difficulty with an erection occurs in approximately 50% to 60% of men with diabetes. Above age 70, there is about a 95% likelihood of having some difficulty with erectile dysfunction.
×