Three longitudinal studies have estimated incidence rates of ED in men with diabetes. Unfortunately, none of these studies specifically examined men with type 2 disease. In a cohort of 278 diabetic men with type 1 or type 2 diabetes potent at study entry, the proportion of patients reporting ED at 5-year follow-up was 28%.7 A follow-up analysis of the Massachusetts Male Aging Study, a community-based cohort of men between 40 and 70 years of age, found that the incidence of ED in the diabetic men was 51/1,000 population-years.8 This figure was similar to the 68/1,000 person-years crude incidence rate of ED reported in a study of 1,010 men with diabetes.5 However, new studies need to be carried out in well-characterized populations of men with diabetes in order to better determine the incidence of ED and potential effects of interventions to reduce complications.
A thorough history (including cardiovascular symptoms, age, presence of risk factors and comorbid conditions such as obesity, hypertension, dyslipidaemia, pre-diabetes, CAD, peripheral artery disease, symptoms suggestive of sleep apnoea, family history of premature atherothrombotic CVD and lifestyle factors), assessment of ED severity (according to SHIM) and duration, and physical examination (for both heart and peripheral circulation pathology) are mandatory first-line elements of investigation. A resting electrocardiogram, measurement of fasting plasma glucose, and estimation of glomerular filtration rate are desirable tests that may be used to further characterize cardiovascular status and risk and to identify men who require additional cardiologic workup. Owing to the accumulating evidence supporting the link with CVD, the measurement of testosterone is recommended in all men with a diagnosis of organic ED, especially in those for whom phosphodiesterase type 5 (PDE5) inhibitor therapy failed.

Oral medicines: The best known ED medications are the Big Three: Viagra (sildenafil citrate, made by Pfizer, Inc.), Levitra (vardenafil HCl, made by Bayer and GlaxoSmithKline), and Cialis (tadalafil, made by Eli Lilly). The three are chemically very similar, and all have proven very effective. Because they are effective, convenient, and relatively inexpensive (about nine dollars per pill), these medicines have become the treatment of choice for most men experiencing ED.
The Epimedium plant is a flowering perennial found throughout Asia and parts of the Mediterranean. Horny Goat Weed’s active ingredient is icariin, a falvonol glycoside and reputed to improve cardiovascular function, hormone regulation, modulation of immunological function and antitumor activity (44). Icariin has also been shown to have a PDE5i effect. Animal studies have been carried out showing improvements in penile hemodynamic parameters. There is one report of tachyarrhythmia and hypomania with the use of this herb (45).

Crossref | PubMed | Google ScholarSee all References After controlling for age, trauma, hypertension, and diabetes mellitus, a study of 97 young patients with ED who underwent selective pudendal angiography showed a significant relationship between lifetime cigarette smoking and the degree of internal pudendal and common penile arterial atherosclerosis.28x28Rosen, MP, Greenfield, AJ, Walker, TG et al. Cigarette smoking: an independent risk factor for atherosclerosis in the hypogastric-cavernous arterial bed of men with arteriogenic impotence. J Urol. 1991; 145: 759–763


Preclinical and clinical trials of these oral agents have clearly demonstrated that they are well tolerated by most DM patients and have an efficacy rate superior to other oral agents. The ultimate result is an improved quality of life (QOL) in EDDM patients. With a greater willingness of DM patients to discuss and seek treatment for ED, it is highly probable that the use of these oral agents will continue to increase. The goal of this article is to provide the physician and pharmacist with a background and working knowledge of these oral agents and their present-day alternatives.
Treatment of ED which was previously confined to invasive procedures, cavernosal injections or to rather ineffective oral medications was revolutionized in 1999 with the introduction of the orally administered PDE5 inhibitor sildenafil. Phosphodiesterase type 5 inhibitors are the first-line therapy for ED of organic aetiology unless there is a specific contraindication to their use. This class of agents is widely used because of its effectiveness and safety.38 Interactions with cardiovascular drugs have been minimal with the exception of nitrates and other nitric oxide (NO) donors (such as nicorandil), where co-administration may result in severe vasodilation and hypotension. However, nitrates are often overused in clinical practice; therefore, the option of their discontinuation should be considered. A strong body of clinical data shows that all three agents (sildenafil, tadalafil, and vardenafil) do not increase the risk of non-fatal myocardial infarction, stroke, or cardiovascular deaths. These drugs do not exacerbate ischaemia or worsen exercise tolerance in patients with known CAD who achieve levels of exercise comparable or greater than that achieved during sexual intercourse.38,39 Phosphodiesterase type 5 is expressed throughout the human body, including the pulmonary and systemic vasculature and hypertrophied myocardium. While currently their only additional indication, beyond ED, is idiopathic pulmonary hypertension (for sildenafil and tadalafil), they show potential to be of benefit in several other conditions, such as CAD and systolic heart failure.39 Mechanisms of benefit of PDE5 inhibitors include pulmonary and systemic vasodilation, increased myocardial contractility, reduced large artery stiffness and wave reflections, improved endothelial function, and reduced apoptosis, fibrosis and hypertrophy through mechanisms involving NO, cyclic guanosine monophosphate, protein kinase G and Rho kinase.39 A very important issue is whether treatment of ED per se (and not of its risk factors and comorbidities) will have an impact on cardiovascular risk. While this applies to all therapeutic modalities of ED, it is particularly pertinent for PDE5 inhibitors, since they represent the mainstay of ED therapy. Data are limited to date. Gazzaruso et al.21 showed a trend of PDE5 inhibitors to reduce cardiovascular morbidity and mortality in diabetic patients with silent CAD and ED, while Frantzen et al.40 showed that 2 years after the introduction of sildenafil, the relative risk of the incidence of CVD among men with ED compared with healthy men significantly decreased from 1.7 to 1.1.
Logically, ED secondary to testosterone deficiency should be treated by testosterone replacement. Testosterone levels in men decrease with age.4 Both epidemiological and observational studies have demonstrated that reduced testosterone is associated with increased cardiovascular risk. One meta-analysis showed lower testosterone and higher 17β oestradiol as significant risk predictors despite adjustment for age and body mass index.4 Patients with coronary artery disease (CAD) have been found to have lower testosterone levels than controls, and there is inverse correlation between testosterone and the incidence of major cardiovascular disease (CVD).4 A significant negative correlation has been reported between total testosterone levels and Framingham risk score.4 However, it has been pointed out that ‘It is unclear if this is a causal association or due to low testosterone being a biomarker of poor health’.4 Testosterone replacement as a treatment for …

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.
Towards this direction, several sufficiently powered studies have demonstrated a higher incidence of erectile dysfunction in patients with coronary artery disease, either asymptomatic or overt. At the same time, patients with erectile dysfunction are more prone to have established coronary artery stenosis of more than 50% and consequently evident CV disease[75]. This is in conformity with the “artery size hypothesis” according to which smaller arteries (e.g., penile arteries) are the first to undergo a vascular lesion prior to the larger ones (e.g., coronary arteries). Moreover, in such patients erectile dysfunction is connected to the number of occluded vessels and more interestingly occurs over three years before coronary artery disease becomes apparent[76-80].
The discovery in 1992 of the second messenger of cavernosal smooth muscle relaxation was the critical step that led to the era of nonhormonal oral drug therapy for ED. In 1998, the multicenter trial of sildenafil in the treatment of ED was published in the New England Journal of Medicine, and the era of the phosphodiesterase type 5 (PDE-5) inhibitor began.1 For 5 years, sildenafil was the primary therapy for men with EDDM. Recently, 2 new PDE-5 inhibitors, vardenafil and tadalafil, were introduced.

Other effective Diabetic Erectile Dysfunction Treatment therapies available include (a) an intraurethral suppository of the vasodilator drug alprostadil (prostaglandin E1), (b) intracavernosal self injection (penile self injection) of the non-specific PDE drug papaverine, the non-selective alpha-adrenergic antagonist phentolamine, and the vasodilator prostaglandin E1, used alone or in combination, or (c) penile prostheses (penile implants).

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.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (272) | Google ScholarSee all References Between 1987 and 1989, the Massachusetts Male Aging Study (MMAS), a community-based random sample observational study of 1709 men, used self-administered sexual activity questionnaires to gather information about noninstitutionalized men aged 40 to 70 years in cities near Boston.4x4Feldman, HA, Goldstein, I, Hatzichristou, DG, Krane, RJ, and McKinlay, JB. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol. 1994; 151: 54–61
Alcohol consumption, bad nutrition, a sedentary lifestyle, excessive stress, psychological issues, relationship issues, use of illegal drugs and overuse of prescribed drugs, poor sleep habits and excessive physical activity are all contributing factors to ED. Ailments like diabetes, as well as low and high blood pressure, in addition to prostate cancer, may also result in ED.
Characteristics that imply a higher risk is severe ED (SHIM 1–7) and ED duration >3 years.15,30 Vascular and circulating biomarkers may help to characterize further the patient with ED.23 Of the wide array of biomarkers that have been proposed for the assessment of cardiovascular risk in asymptomatic adults,34,35 some have been studied specifically in the context of ED.23Table 4 offers a critical evaluation of these biomarkers. Such tests should be considered as potentially helpful and thus recommended where available, but not mandatory.30 Despite its potent predictive ability recently shown,36 exposure to radiation with coronary artery calcium scoring should be carefully weighed. Although not specific for ED, it might be reasonable to evaluate biomarkers that have been proposed for the intermediate-risk patient such as uric acid, glycated haemoglobin, microalbuminuria, and lipoprotein-associated phospholipase A2.30
Overall, sildenafil appears to be relatively safe and effective for treatment of ED in men with stable cardiovascular disease who are not taking NO-donor medications. In a study of 105 men with ED and known or likely coronary artery disease, patients underwent symptom-limited supine bicycle echocardiography 2 times after receiving either sildenafil or placebo.63x63Arruda-Olson, AM, Mahoney, DW, Nehra, A, Leckel, M, and Pellikka, PA. Cardiovascular effects of sildenafil during exercise in men with known or probable coronary artery disease: a randomized crossover trial. JAMA. 2002; 287: 719–725
Oral medications (Viagra™, Cialis™, Levitra™ and Stendra™) are a common first step to treat ED, but they don’t work for everyone – especially men with heart disease. Men taking nitrates for heart disease or those taking alpha blocking agents for blood pressure are generally not candidates for oral ED medication.13 In addition, some medications simply do not work for certain men. When ED medication is not the answer, there are other options.
Chronic heart failure often develops after other cardiac problems have damaged or weakened the heart, leaving it too weak or too stiff to fill and pump efficiently. Many underlying heart conditions can lead to heart failure. It can develop quickly after damage caused by a heart attack, or it can develop gradually after years of high blood pressure or coronary artery disease.
Crossref | PubMed | Scopus (71) | Google ScholarSee all References However, a double-blind, placebo-controlled study of 22 middle-aged men with hypercholesterolemia treated for 6 weeks with pravastatin or lovastatin showed improved erectile function with both medications.54x54Kostis, JB, Rosen, RC, and Wilson, AC. Central nervous system effects of HMG CoA reductase inhibitors: lovastatin and pravastatin on sleep and cognitive performance in patients with hypercholesterolemia. J Clin Pharmacol. 1994; 34: 989–996
Severe testosterone deficiency, known as “hypogonadism,” is present in approximately 2–35% of men with erectile dysfunction.19 However, lesser degrees of deficiency are common, perhaps present in the majority, depending on the definition of “low” applied, the method of measurement, and the parameter being used to define testosterone (total, free, or bioavailable) deficiency.19,20 Most authorities agree that a total testosterone level below 300 ng/dL is clearly low, and that 300–400 ng/dL is low to low-to-normal. Most studies using testosterone replacement for erectile dysfunction have attempted to achieve blood levels of 450–850 ng/dL.
Having chronically high blood pressure can affect overall satisfaction with sex and affect men’s ability to achieve a firm erection. Due to constant vessel damage as a result of high blood pressure, linings of the arteries begin to harden and narrow, a process called atherosclerosis. Because blood flow is limited to the affected regions of the body, arterial blood circulation to various organs—including the heart muscles, brain, and even the groin—can be compromised, with myocardial infarctions, strokes, and erectile difficulty being common in hypertensive patients. Studies show that approximately 30 percent of hypertensive patients reported having erectile dysfunction, and approximately 49 percent of men aged 40 to 79 had both high blood pressure and ED.

Cardiovascular disease remains our nation’s biggest killer, responsible for about one-third of deaths in the U.S.1 Erectile dysfunction (ED) is typically the first clinical manifestation of cardiovascular disease, making it a helpful early marker for men who are likely to die of heart attacks. There is a strong relationship between erectile dysfunction and high blood pressure, high cholesterol, angina, stroke, heart attack and a premature death.2, 3


Crossref | PubMed | Google ScholarSee all References These hormonal findings were supported by a study of 1132 men aged 30 to 79 years that found an inverse relationship between blood pressure and serum testosterone levels.32x32Khaw, KT and Barrett-Connor, E. Blood pressure and endogenous testosterone in men: an inverse relationship. J Hypertens. 1988; 6: 329–332
 Other treatment options such as penile self-injection therapy, external vacuum pumps and the medicated urethral system for erection are on rare occasions an effective long-term treatment. A very small percentage of men will continue with these treatments as evidenced by a very high drop out rate and a very low refill rate for these treatments. These procedures require extensive planning which interfere with sexual spontaneity and are really not a realistic long-term treatment for young patients with permanent ED. 
Testosterone therapy in hypogonadism modulates metabolic components associated with CV risk. The majority of prospective clinical studies indicates that treatment achieving testosterone levels within physiological limits has beneficial or neutral effects on a lipid profile other than HDL-C, beneficial or neutral effects on inflammatory mediators, and generally beneficial effects on glycaemic state.25 The lean body mass is typically increased in hypogonadal subjects, and visceral adiposity is decreased in several studies and unchanged in the remainder. Such metabolic effects have raised interest on the potential impact on cardiovascular health. Regarding symptoms in patients with pre-existing cardiovascular conditions (angina or heart failure) TTh has been either neutral or beneficial.25 Regarding CVD risk, available clinical trial data indicate that the use of testosterone in middle-aged to elderly men does not increase cardiovascular risk25 with the exception of one study in very frail (substantial limitation of mobility and a high rate of comorbidities) elderly subjects that used an off-label high, and rapid escalation, dosing regimen.46 Prospective data from large, well-designed, long-term trials of TTh are warranted.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References The use of any NO-donor medications should be avoided for 24 hours after the last dose of sildenafil and even longer if there is a suspected prolonged half-life secondary to such conditions as renal insufficiency.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
Hypertension can affect endothelial function in many ways. It can reduce endothelium-dependent vasodilatation by increasing the vasoconstrictor tone as a result of increased peripheral sympathetic activity.41–43 Another mechanism is hypertension-induced increase in cyclooxygenase activity that leads to an increase in reactive oxygen species; these in turn damage endothelial cells and disrupt their function.44–46 In some cases, endothelial NO synthase (eNOS) gene variations may relate to hypertension-associated endothelial dysfunction.6
Abstract | Full Text | Full Text PDF | PubMed | Scopus (30) | Google ScholarSee all References Penile sympathetic stimulation flows through several pathways, including the sympathetic chain ganglia, which also supply such structures as the heart and vascular system. Sympathetic tone precipitates release of norepinephrine from penile adrenergic nerves, resulting in tonic contraction of cavernosal smooth muscle and its vasculature, thereby keeping the penis flaccid.9x9Andersson, K and Stief, C. Penile erection and cardiac risk: pathophysiologic and pharmacologic mechanisms. Am J Cardiol. 2000; 86: 23F–26F
Nehra A,  Jackson G,  Miner M,  Billups KL,  Burnett AL,  Buvat J,  Carson CC,  Cunningham GR,  Ganz P,  Goldstein I,  Guay AT,  Hackett G,  Kloner RA,  Kostis J,  Montorsi P,  Ramsey M,  Rosen R,  Sadovsky R,  Seftel AD,  Shabsigh R,  Vlachopoulos C,  Wu FC. The Princeton III Consensus recommendations for the management of erectile dysfunction and cardiovascular disease, Mayo Clin Proc , 2012, vol. 87 (pg. 766-778)https://doi.org/10.1016/j.mayocp.2012.06.015

When it comes to scientific development, in Western medicine, an analytic approach is often used to identify and resolve medical challenges. A hypothesis is first derived through general observations of a phenomenon. A research plan is then carefully designed and data collected. Once sufficient data is collected, critical statistical evaluations are done and conclusions are drawn (4). Every aspects of a disease entity are studied from macroscopic to microscopic views, down to the cellular and molecular levels. The deep understanding of the role of cGMP-specific phosphodiesterase type 5 enzymes in ED and the use of phosphodiesterase-5 inhibitors in treatment of ED exemplifies the success of this approach.
Combination therapy has proven effective for some men who don’t respond adequately to oral medicines. The idea is to use two drugs with different mechanisms of action for better results. Commonly, sildenafil is used in combination with pellets of alprostadil (synthetic prostaglandin E1) that are inserted into the urethra (the tube in the penis that carries urine from the bladder to the outside of the body). Alprostadil also increases the blood supply to the penis, but by different means.
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