These drugs are safe for healthy hearts, but all men with cardiovascular disease should take special precautions, and some cannot use them under any circumstances. The problem is their effect on arteries. All arteries, not just those in the penis, generate nitric oxide, so any artery can widen in response to Viagra, Levitra, or Cialis, causing blood pressure to drop temporarily by 5-8 mmHg, even in healthy men.
The great majority of ED cases in diabetic men have a physical cause, such as neuropathy or circulatory problems. In some cases, however, the cause of ED is psychological, including depression, guilt, or anxiety. With a thorough exam, the doctor should be able to determine whether the ED is psychological or physical in nature. If the cause is psychological, your doctor may refer you to a psychiatrist, psychologist, sex therapist, or marital counselor. Do not view such a diagnosis as an insult. Most psychologically-based ED is easily and successfully treated.
As a primary care doctor, my most important job is to tailor treatment for my patients while still making decisions based on the medical literature. So when patients tell me their treatment is causing undesired side effects—like ED—I work with them to create a plan to treat the condition while also finding a way to relieve those side effects. Fortunately, there are ways to deal with medically induced ED.
The second way relates to the risk associated with the sexual activity in a patient with either overt or occult CVD. In this case, the diagnosis of ED should prompt an initial cardiovascular assessment based on the history and clinical examination in order to define the baseline risk according to (i) the likelihood of silent CAD18,31 (especially since ED patients have a high probability to have silent CAD) or to the stage of clinically evident CAD, (ii) other cardiovascular conditions either unrelated, or related to ED (e.g. heart failure, peripheral arterial disease).
Penile erection is largely a vascular process, and the penile endothelium and smooth muscle tissue are very sensitive to functional and structural changes. Vasculogenic ED results from an impairment of endothelial dependent or independent smooth muscle relaxation (functional vascular ED, initial stages), occlusion of the cavernosal arteries by atherosclerosis (structural vascular ED, late stages), or a combination of these.3 Current data support a complex interplay between endothelial dysfunction, subclinical inflammation, and androgen deficiency (Figure 1). The relationship between ED and CAD at the clinical level is supported by this common pathophysiological basis. The ‘artery size’ hypothesis explains why patients with CAD frequently report ED before CAD detection.10 According to this hypothesis, for a given atherosclerotic burden, the smaller penile arteries suffer obstruction earlier than the larger coronary arteries (Figure 2). The same concept holds also true in the case of non-obstructing atherosclerosis: since the smaller penile artery have a greater endothelial surface and erection requires a large degree of vasodilation to occur when compared with arteries in other organs, the same degree of endothelial dysfunction will be symptomatic in these smaller vessels but subclinical in the larger ones (i.e. coronaries). In the same context, accelerated arterial ageing (as indicated by increased arterial stiffening that also affects large arteries of ED patients) may be a common background.11,12 Erectile dysfunction is associated with an incremental inflammatory and endothelial-pro-thrombotic activation.13 Interestingly, this activation is equal to that found in CAD patients with no ED, while when these two conditions are combined the burden is additive. Androgen deficiency may be also implicated in the common pathogenetic pathways of ED and CVD; however, this warrants further substantiation.2
The pilot study by Vardi et al. (18) showed that LIESWT was effective in treating men with ED, suggesting a physiologic impact of LIESWT on cavernosal hemodynamics. The LIESWT is an effective penile rehabilitation tool that improves erectile function and potentially reverses underlying ED. Recent meta-analysis (19) of 14 studies showed that LiESWT could significantly improve the International Index of Erectile Function (IIEF) [mean difference: 2.00; 95% confidence interval (CI), 0.99–3.00; P<0.0001] and Erection Hardness Score (EHS) (risk difference: 0.16; 95% CI, 0.04–0.29; P=0.01). In addition, the therapeutic efficacy was noted to last for at least 3 months. LiESWT has been cited to a potential cure for ED, unlike other well established non-surgical methods of treatment (i.e., PDE5i, ICI and VED) being on demand treatments.

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


Abstract | Full Text | Full Text PDF | PubMed | Scopus (30) | Google ScholarSee all References Erections result from relaxation of the corpora cavernosa, which is mediated either by increasing intracellular cyclic guanosine monophosphate (cGMP) or cyclic adenosine monophosphate or by inhibition of their degradation. Increased parasympathetic tone results in a decrease in norepinephrine release and an increase in the release of acetylcholine; subsequently, NO synthase activity increases, which releases NO from both endothelial cells and nonadrenergic, noncholinergic neurons.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N


Low intracavernosal nitric oxide synthase levels are found in people with diabetes, smokers, and men with testosterone deficiency. Interference with oxygen delivery or nitric oxide synthesis can prevent intracavernosal blood pressure from rising to a level sufficient to impede emissary vein outflow, leading to an inability to acquire or sustain rigid erection. Examples include decreased blood flow and inadequate intracavernosal oxygen levels when atherosclerosis involves the hypogastric artery or other feeder vessels and conditions, such as diabetes, that are associated with suboptimal nitric oxide synthase activity.
Obesity is a strong predictor of ED as it is associated with other risk factors, such as diabetes, hyperlipidaemia and hypertension.4 Obesity increases the risk of ED by 30–90 % and acts as an independent risk factor for CVD. Obese men with ED have greater impairment in endothelial function than non-obese men with ED.5 Moreover, high BMI causes low testosterone levels, which in turn leads to ED, as observed in a prospective trial involving 7,446 participants.50
Another study showed a forty percent increase of blood flow to the heart within one year of starting a dietary program designed similar to the one described in my book, The End of Heart Disease. Of pertinent note is that, in the same study, the patients following a high-protein Atkins’ diet decreased blood flow to the heart by forty percent in one year.8 These dangerous high-protein diets are a certain path to erectile impotence and a premature cardiac death.
PubMed | Google ScholarSee all References They evaluated 40 patients with coronary artery disease who underwent coronary artery catheterization and whose penile brachial index (PBI) was measured by Doppler ultrasonography. Although a positive correlation was noted between the PBI and the severity of coronary artery obstruction, the relationship was not strong. Also, the degree of PBI abnormality did not effectively stratify the patients according to the severity of their coronary artery blockage. This study concluded that the PBI used alone would not be an effective predictor of ischemic heart disease.
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.
Currently, the preferred treatment for erectile dysfunction includes sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis). However, numerous experts have raised concerns about the use of these drugs in patients with chronic heart failure who also take nitrates (or other medications that relax and widen blood vessels). This drug combination has been shown to be dangerous, because it can increase the risk for a life-threatening drop in blood pressure.
With atherosclerosis, the blood vessels are not able to dilate properly, which is called endothelial dysfunction (see the Figure). Cholesterol builds up in the blood vessel walls and forms plaques, which make the vessels narrow and slow down blood flow. When a plaque becomes very advanced, it can completely stop blood from passing through, which is what happens in a heart attack. Atherosclerosis affects not only the blood vessels supplying the heart (coronary arteries), but also blood vessels throughout the entire body. Atherosclerosis causes angina (chest pain that is often exertional), heart attacks, strokes, claudication (pain in the legs with walking), and ED. Atherosclerosis affects different people in different places, but it often affects the penis first, then the heart and brain, and the legs last. Because the first stage of atherosclerosis, endothelial dysfunction, usually affects the penis first, ED can be a warning sign that a heart attack or a stroke may follow, often in the next 3 to 5 years. This warning sign can be a good thing if it alerts you and your doctor that you have atherosclerosis, because then you can take steps to treat the atherosclerosis and prevent a heart attack or stroke.
If you take a diuretic, you should stay on it until high blood pressure is under control. If erection problems persist, or blood pressure goes back up, then your doctor might switch to a drug that's less likely to cause erectile dysfunction. Or, a combination of medications might work better to control high blood pressure and lower the risk of erectile dysfunction.
Diabetes, high blood pressure (hypertension), elevations in blood lipids or cholesterol are considered blood vessel problems and have all been associated with Erectile Dysfunction. The blood vessel abnormalities caused by these diseases affect vessels throughout the body and often produce other symptoms of vascular diseases. Diabetics and patients with hypertension frequently have heart disease. These conditions typically interfere with the ability of the penile vessels to work properly and ultimately cause ED.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Diabetic damage doesn’t stop with these small vessels, he said. “You really have two parallel situations: You need blood flow that feeds the muscle of the penis, and you need an artery dedicated to bringing blood rapidly when a man becomes aroused and wants to be sexually active,” he said. “That artery is also affected by diabetes. They’ll say ‘I can get a partial erection, but I can’t maintain it.’ ”
Abstract | Full Text | Full Text PDF | PubMed | Scopus (66) | Google ScholarSee all References Risk of arrythmias after sexual intercourse was evaluated in 82 patients with stable coronary artery disease who were monitored with ambulatory ECG after sexual intercourse.81x81Drory, Y, Fisman, EZ, Shapira, Y, and Pines, A. Ventricular arrhythmias during sexual activity in patients with coronary artery disease. Chest. 1996; 109: 922–924
Stem cell therapy is an attractive treatment modality and an appealing option for tissue regenerative therapy for ED. Stem cells are pluripotent cells that can be produced from multiple regions within the body. They have the potential to divide and differentiate into numerous kinds of human cells, such as endothelial cells and smooth muscle.79 The efficacy and safety of gene and stem cell therapy in patients with ED and IHD need to be extensively investigated because both seem to have the potential to correct underlying abnormalities in ED. This would be a huge development in terms of management options for patients with ED and IHD.
A man needs to try the medicine at least four times before he concludes that it doesn’t work for him. It is unlikely that a man with diabetes who has other medical problems such as high blood pressure, is taking multiple medicines, and has not had sexual intercourse for several years will be able to have an erection adequate for intercourse the first time he takes a pill. Most men need to try the medicine several times before they have the desired results.
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