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.
Low testosterone levels have been observed inconsistently in STZ-induced diabetic and BB rats.18 Androgen deficiency in rats is associated with downregulation of the neuronal isoforms of nitric oxide synthase, suggesting a trophic effect of testosterone on peripheral erectile tissues. In humans, androgens play a larger role in sexual interest and motivation (libido) than in erectile capacity itself; penile erection is more resistant to androgen withdrawal than is sexual desire.19,20
In diabetic patients who fail medical management of ED, penile implantation surgery remains a viable therapeutic option. In a recent review of 372 men who underwent implantation of a three-piece inflatable penile implant, 86% reported that the device was still functional 5 years after implantation, and 79% reported that they used the device at least twice monthly.59
Conversely, and of significant clinical importance, is how often patients with ED as their first and sole clinical manifestation suffer from subclinical CAD.17 Previous studies reported a rate of inducible ischaemia by exercise stress testing (EST) in 22% (with a wide range of 5–56%) of ED patients reflecting differences in patient population, risk factors and criteria used for ED and CAD diagnosis. Interestingly, those patients further assessed with coronary angiography had obstructive atherosclerosis in >90% of cases.4,18 In a prospective angiographic study, we documented that 19% of ED patients suffer from clinically silent obstructive CAD.18
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).
80. Montorsi F, Briganti A, Salonia A, Rigatti P, Margonato A, Macchi A, Galli S, Ravagnani PM, Montorsi P. Erectile dysfunction prevalence, time of onset and association with risk factors in 300 consecutive patients with acute chest pain and angiographically documented coronary artery disease. Eur Urol. 2003;44:360–364; discussion 364-365. [PubMed]

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.
Before Viagra hit the market in 1998, there was no proven treatment for erectile dysfunction that men could take in pill form. Doctors were interested in yohimbe, an herb that increases heart rate and blood pressure. Some doctors prescribed it to their patients in combination with other treatments for erectile dysfunction. Even then it was not a recommended treatment and is still not today. Studies have not proven that it works.
Crossref | PubMed | Scopus (1) | Google ScholarSee all References Angiotensin-converting enzyme inhibitors also have low rates of secondary ED associated with their use in both animal and human studies.45x45Srilatha, B, Adaikan, PG, Arulkumaran, S, and Ng, SC. Sexual dysfunction related to antihypertensive agents: results from the animal model. Int J Impot Res. 1999; 11: 107–113
After getting a diagnosis of ED, most patients can begin treatment right away, but treatment may be delayed for some patients until the health of the heart is more fully assessed or improved. The most common treatment for ED is a pill (phosphodiesterase-5 inhibitor; PDE5-I): Viagra (sildenafil), Cialis (tadalafil), or Levitra (vardenafil). Each of these pills improves erections when taken before sexual activity; alternatively, a low dose of Cialis can be taken once a day. These medicines work by allowing the blood vessels that supply blood to the penis to dilate better during sexual stimulation. The PDE5-Is decrease blood pressure a little bit, but they are safe with most other medications and with other blood pressure pills. The PDE5-Is are not safe with nitrate medications like nitroglycerin, Nitrostat, Nitro Paste, Imdur, isosorbide mononitrate, and Isordil. Mixing a PDE5-I with a nitrate medication could result in severely low blood pressure and even death. Inform all medical professionals (including the ambulance or emergency department) about your most recent ED pill ingestion so that nitrates can be avoided. If you have high blood pressure or benign prostatic hypertrophy (enlarged prostate) and take medicines called α-blockers, your doctor may need to start you on the lowest dose of the PDE5-I.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (66) | Google ScholarSee all References However, some researchers have questioned whether the strain of sexual activity can be compared accurately with standard types of physical activity and whether sexual activity is more closely related to episodes of anger or fear.85x85DeBusk, RF. Evaluating the cardiovascular tolerance for sex. Am J Cardiol. 2000; 86: 51F–56F
While all three forms of male sexual dysfunction can be found among diabetic men, this review will focus on the most common form, ED, because the literature is most mature in this area. Defined as the inability to achieve or maintain an erection sufficient for satisfactory sexual performance, ED is highly prevalent in diabetic men1 and is almost always organic in its etiology. Given that many patients feel that their ED is “in their heads” and that “their provider will dismiss any sexual problems they might bring up,”2 it may be a relief for patients to learn that their ED is physical, related to their diabetes, and treatable. To this end, the goal of this article is to review the epidemiology, pathophysiology, quality of life effect, and treatment of ED in men with type 2 diabetes.

Luckily, awareness of ED as a significant and common complication of diabetes has increased in recent years, mainly because of increasing knowledge of male sexual function and the rapidly expanding armamentarium of novel treatments being developed for impotence. Studies of ED suggest that its prevalence in men with diabetes ranges from 35–75% versus 26% in general population. The onset of ED also occurs 10–15 years earlier in men with diabetes than it does in sex-matched counterparts without diabetes.
Crossref | PubMed | Scopus (539) | Google ScholarSee all References After adjusting for age, vascular disease, psychiatric disease, hormonal factors, and marital status, a study of 4462 US Army veterans aged 31 to 49 years found an odds ratio of 1.8 for the risk of developing ED in men who smoked.26x26Mannino, DM, Klevens, RM, and Flanders, WD. Cigarette smoking: an independent risk factor for impotence?. Am J Epidemiol. 1994; 140: 1003–1008
Prescription drugs called “oral phosphodiesterase-5 (PDE5) inhibitors” are considered the “first-line non-invasive treatment” options for patients with ED. These include the drugs that go by brand names: Sildenafil, Vardenafil or Tadalafil. They work by helping the smooth muscle cells lining the blood vessels that supply the penis with blood to work properly. This allows a man to maintain an erection more easily.
A collection of risk factors that strongly predict heart disease—termed the metabolic syndrome—is also associated with erectile dysfunction. An increasingly prevalent condition, this syndrome includes low HDL, increased triglycerides, high blood sugar, and heightened inflammation and causes a three-fold or greater risk of heart attack, stroke, and diabetes. It is largely attributable to excess weight, poor diet, and inactivity and afflicts at least 47 million Americans, signaling that an epidemic of erectile dysfunction is sure to follow. Indeed, a survey of 2,400 men participating in a health screening revealed that metabolic syndrome increases the likelihood of erectile dysfunction by 48%.10
Abstract | Full Text | Full Text PDF | PubMed | Scopus (56) | Google ScholarSee all References Of 1774 patients with a history of myocardial infarction, only 2 who had experienced a myocardial infarction after sexual intercourse were able to exercise to at least 6 METs without symptoms.8x8Muller, JE, Mittleman, A, Maclure, M, Sherwood, JB, Tofler, GH, and Determinants of Myocardial Infarction Onset Study Investigators. Triggering myocardial infarction by sexual activity: low absolute risk and prevention by regular physical exertion. JAMA. 1996; 275: 1405–1409
Erectile dysfunction supplements and other natural remedies have long been used in Chinese, African and other cultures. But unlike prescription medications for erectile dysfunction, such as sildenafil (Viagra), vardenafil (Levitra, Staxyn), tadalafil (Cialis, Adcirca) and avanafil (Stendra), erectile dysfunction herbs and supplements haven't been well-studied or tested. Some can cause side effects or interact with other medications. And the amount of the active ingredient can vary greatly from product to product.
Unfortunately, government agencies often are slow to respond to new scientific information and economic and political forces make it difficult for our population to receive clear information informing them that heart disease is nutritionally induced and totally avoidable with dietary excellence. Sadly, even the American Heart Association advocates a diet that has been shown to actually increase heart disease.
Your doctor may also choose to lower your dose of certain medications. Or your provider may switch the type of drug you’re taking if it’s interfering with your sex life. Some medicines used for managing blood pressure, insomnia, anxiety, depression, seizures and prostate problems increase the risk for erectile dysfunction. Beta-blockers (for high blood pressure), SSRIs (often used to treat depression) and the class of drugs called benzodiazepines (like Ativan, Xanax, Librium and Valium) are commonly tied to ED. You may want to speak to your doctor about this.
Crossref | PubMed | Scopus (23) | Google ScholarSee all References Vardenafil has been shown to be significantly more effective than placebo in the treatment of ED secondary to diabetes mellitus and after radical retropubic prostatectomy.69x69Goldstein, I, Young, JM, Fischer, J, Bangerter, K, Segerson, T, Taylor, T, and Vardenafil Diabetes Study Group. Vardenafil, a new phosphodiesterase type 5 inhibitor, in the treatment of erectile dysfunction in men with diabetes: a multicenter double-blind placebo-controlled fixed-dose study. Diabetes Care. 2003; 26: 777–783
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Sildenafil has a 4000-fold increased selectivity for PDE-5 over PDE-3, has negligible effects on heart rate, and has only a modest effect on blood pressure level in healthy persons, with an average systolic pressure decrease of 10 mm Hg with a single dose of 100 mg.3x3Zusman, RM, Morales, A, Glasser, DB, and Osterloh, IH. Overall cardiovascular profile of sildenafil citrate. Am J Cardiol. 1999; 83: 35C–44C
The use of shock wave therapy has revolutionized the treatment of many aspects of medicine. High intensity extracorporeal shockwave therapy has been used for the treatment of nephro-urolithiasis while medium intensity shockwave therapy is used by orthopaedic surgeons to treat joint pain as well as tendinitis. Low intensity shockwaves therapy was first noted to improve ischaemia-induced myocardial dysfunction in animal studies when low intensity shockwaves were applied to porcine myocardium (13). Shockwaves induces a localized stress on cell membranes in the same way that shear stress affects endothelial cell membranes (14) and this triggers the release of angiogenic factors, such as increased NO production through increased activity of endothelial NO synthase (eNOS) and neuronal NO synthase (nNOS), platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) (15). These shockwaves also cause membrane hyperpolarization (16), activation of the Ras signaling pathway, non-enzymatic synthesis of NO and induction of stress fibers and intercellular gaps (17).
ED can be caused by many things. The most common causes in men with diabetes are problems related to blood vessel– and nerve-related complications. Sometimes, though rarely, ED can be caused by a hormonal imbalance. Depression can also cause ED, as can stress and excessive worrying about sexual performance. Certain medications can cause temporary ED.

Erectile dysfunction is a common occurrence in men with diabetes. The incidence of erectile dysfunction increases progressively with age, from 5% in men age 20 to 75% in men over age 65. The cause of erectile dysfunction in men with diabetes is usually related to a decrease in the blood supply to the penis as well as to injury to the nerves that are responsible for the erection mechanism. A decrease in testosterone production has also been identified as the cause in some men with diabetes.
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