Erection is a neurovascular event that involves spinal and supra spinal pathways. The final common pathway involves the release of nitric oxide (NO) from both endothelial cells and neurons, which acts as a vasodilator causing penile engorgement and erection. NO is degraded by the enzyme phosphodiesterase (PDE) type 5 in the penis. Erectile dysfunction (ED), defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance, results when the neurovascular pathway is interrupted by medical conditions or drugs. A 15-item self-administered questionnaire, the International Index of Erectile Function (IIEF), is one of the most useful tools to evaluate erectile function (EF) in clinical trials, although of much less use in routine clinical practice. The MMAS (Massachusetts Male Aging Study) was the first major epidemiological investigation to study the prevalence of ED. The study found that ED was three times more common in patients with diabetes mellitus. The aetiopathogenesis of ED in diabetes is multifactorial, with vascular and neural factors being equally implicated. Hyperglycaemia is believed to give rise to biochemical perturbations that lead to these microvascular changes. In the MMAS, ED in diabetes was strongly correlated with glycaemic control, duration of disease and diabetic complications. The incidence increased with increasing age, duration of diabetes and deteriorating metabolic control, and was higher in individuals with type 2 diabetes than those with type 1.ED in men with diabetes often affects their quality of life and, as patients are often reluctant to come forward with their symptoms, a carefully taken history is one of the most useful approaches in identifying affected individuals. The PDE inhibitors have revolutionised the management of ED and oral drug therapy is currently first-line therapy for the condition. These agents act by potentiating the action of intracavernosal NO, thereby leading to a more sustained erection. Sildenafil was the first PDE5 inhibitor to undergo evaluation and has been studied extensively. More recently two other agents, vardenafil and tadalafil, have been introduced. All the drugs have been shown to be effective across a wide range of aetiologies of ED, including diabetes. The drugs have been shown to improve EF domain scores, penetration and maintenance of erection, resulting in more successful intercourse. Their effects are greater at higher doses. Sildenafil and vardenafil are shorter-acting agents, while tadalafil has a longer half-life allowing the user more flexibility in sexual activity. Common adverse effects include headache, nasal congestion and dyspepsia, all actions related to inhibition of PDE5. The drugs are generally well tolerated and withdrawal from the clinical studies as a result of drug-related adverse effects were rare. The use of PDE5 inhibitors in the presence of oral nitrates is absolutely contraindicated. The clinical studies to date have not evaluated the use of one drug in the case of treatment failure with another agent. Sublingual apomorphine, which stimulates central neurogenic pathways, is a new agent and may be a suitable alternative in those patients in whom PDE5 inhibitors are ineffective or contraindicated. In clinical trials, all IIEF domains except sexual desire were found to have improved after apomorphine. The median times to erection in these studies were 18.9 and 18.8 minutes for the 2 and 3mg doses, respectively. Intraurethral and intracavernosal alprostadil may be a useful alternative when oral drug therapy is ineffective or contraindicated. The management of ED in the diabetic patient may often involve a multidisciplinary approach where psychosexual counselling and specialist urologist advice is required in addition to the skills and expertise of the diabetologist. Finally, the introduction of the new oral agents have completely revolutionised the management of ED and allowed more individuals to come forward for treatment.
Crossref | PubMed | Scopus (539) | Google ScholarSee all References The MMAS 9-year follow-up study has shown that a body mass index of 28 kg/m2 or higher was an independent predictor for ED, with an adjusted odds ratio of 1.96.5x5Feldman, 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
A similar situation develops in the fragile penile circulation. Any disturbance in nitric oxide production lowers the capacity to dilate penile arteries, impairing penile engorgement for erection. Release of nitric oxide is readily sabotaged by many conditions, including elevated levels of cholesterol, high blood pressure, increased triglycerides, smoking, metabolic syndrome and diabetes, and excessive consumption of dietary saturated fat.9 If an artery’s inner wall can’t produce nitric oxide, an abnormal constriction of the arteries to the penis follows, effectively choking off blood flow.
Contraindications for TTh include (for detailed listing, please refer to Buvat et al.45) patients with breast or prostate cancer, while patients with a palpable prostate nodule or induration, or prostate-specific antigen >4 ng/mL (or >3 ng/mL in men at high risk for prostate cancer, such as African-Americans or men with first-degree relatives with prostate cancer), should first undergo urological evaluation. Testosterone therapy is contraindicated also in patients with haematocrit >50% (TTh increases haematocrit) and uncontrolled congestive heart failure (risk of fluid retention). Risk for adverse CVD events may be increased in patients and with the mode of treatment epitomized in the study of Basaria et al.46 (see earlier).

It's an all too common problem: Roughly half of men with diabetes—and up to 25 percent of men overall—experience erectile dysfunction (ED) at some point in their lives. And it's a complicated problem, too, with diverse physical origins and complex emotional ramifications. Yet diabetes-related ED needn't be a no-sex sentence for men. There are ways to avoid this disorder and to treat it at any age. While much of the research on ED is still in its infancy, here is what science has to say so far.
A nutrient-dense, plant-rich (Nutritarian) diet is a huge defense. When men eat for optimal health, they protect their heart, prostate, brain, and, in effect, the entire body. A nutrient-dense, plant-rich (Nutritarian) diet floods the body with protective nutrients, and supports a healthy weight. It not only normalizes risk factors for heart disease and diabetes, but also offers a substantial level of protection against common cancers.
Ginkgo biloba. Known primarily as a treatment for cognitive decline, ginkgo has also been used to treat erectile dysfunction -- especially cases caused by the use of certain antidepressant medications. But the evidence isn't very convincing. One 1998 study published in the Journal of Sex & Marital Therapy found that it did work. But a more rigorous study, published in Human Pharmacology in 2002, failed to replicate this finding. "Ginkgo has come out of fashion in the past few years," says Ronald Tamler, MD, assistant professor of medicine and codirector of the men's health program at Mount Sinai Medical Center in New York City. "That's because it doesn't do much. I can say that in my practice, I have not seen ginkgo work -- ever."
The medications used to treat high blood pressure do not take into account the symptoms of erectile dysfunction, as their intention is to lower the blood pressure to a more manageable state, reducing the stress put on blood vessels. High blood pressure and ED are seen as separate entities, with the former taking priority for pharmaceutical treatment. This means that the medications used might do nothing to cure erectile dysfunction and may, in fact, prolong it. Medications that lower blood pressure might actually cause a low blood pressure state in the groin area and the arteries supplying the penis, making it near impossible to achieve an erection. The following are examples of such medications:
Crossref | PubMed | Scopus (77) | Google ScholarSee all References Nitroglycerin is a vasodilator that is commonly used as an antianginal agent because of its ability to improve the imbalance between myocardial oxygen supply and demand.65x65Stamler, JS, Loh, E, Roddy, MA, Currie, KE, and Creager, MA. Nitric oxide regulates basal systemic and pulmonary vascular resistance in healthy humans. Circulation. 1994; 89: 2035–2040
After analyzing 28 previous studies on the link between ED and heart disease, the researchers found a connection between erectile dysfunction and poor endothelial function. “Blood vessels are unable to fully dilate and allow blood to flow through,” explains Medicalnewstoday.com. “Endothelial dysfunction is an early sign of atherosclerosis, a condition in which plaque builds up in the arteries, raising the risk of heart attack and stroke.” The researchers also determined that there was a thickening of one of the inner two layers of the carotid artery—another heart-disease indicator.

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
Abstract | Full Text PDF | PubMed | Scopus (29) | Google ScholarSee all References After controlling for diabetes mellitus, tobacco use, and hyperlipidemia, hypertension was not found to be an independent predictor of vasculogenic ED in 440 impotent men as measured by the PBI.7x7Virag, R, Bouilly, P, and Frydman, D. Is impotence an arterial disorder? a study of arterial risk factors in 440 impotent men. Lancet. 1985; 1: 181–184
Abstract | Full Text | Full Text PDF | PubMed | Scopus (395) | Google ScholarSee all References Phosphodiesterase type 5 is primarily responsible for the breakdown of cGMP in cavernosal tissues. The inhibition of PDE-5 by sildenafil therefore causes continued activation of the NO-cGMP pathway in the cavernosal tissue, thereby improving erectile function.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
In most men, ED is recognised as sharing vascular aetiology with IHD.17 ED and IHD share common risk factors, such as hypertension, hyperlipidaemia, diabetes, obesity, lack of physical exercise, cigarette smoking, poor diet, excess alcohol consumption and psychological stress, including depression.30 Endothelial dysfunction has been implicated as a common mechanism between CAD and ED and it has an important role in the development of atherosclerosis.31
The bottom line is that nearly all men with diabetes who wish to have an erection adequate for sexual intercourse can do so with the therapies currently available. And with commitment and communication, the experience of erectile dysfunction can be changed from a potential personal tragedy to an opportunity for greater emotional intimacy in a couple.
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