The impact of third-generation cardioselective beta-blockers such as carvedilol and nebivolol has also been investigated. Fogari et al. investigated the effect of carvedilol on erectile function in a double-blind crossover study involving 160 men newly diagnosed with hypertension and found chronic worsening of sexual function in those treated with carvedilol compared with valsartan and placebo.24

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.
Sildenafil should be taken 1–2 h before intercourse. It is important to tell patients that the drug’s effectiveness requires sexual stimulation. One patient in our clinic recently complained that he had no effect from taking sildenafil. It was later discovered that he took the pill and then sat on his couch and read a book about how to grow tomatoes!
A medical history focused on risk factors, such as cigarette smoking, hypertension, alcoholism, drug abuse, trauma, and endocrine problems including hypothyroidism, low testosterone levels, and hyperprolactinemia, is very important. Commonly used drugs that disrupt male sexual function are spironolactone (Aldactone), sympathetic blockers such as clonidine (Catapres), guanethidine (Islemin), methyldopa (Aldomet), thiazide diuretics, most antidepressants, ketoconazole (Nizoral), cimetidine (Tagamet), alcohol, methadone, heroin, and cocaine. Finally, assessment of psychiatric history will help identify emotional issues such as interpersonal conflict, performance anxiety, depression, or anxiety.
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).
Red Ginseng — One small randomized trial found evidence that red ginseng may offer modest improvements in ED symptoms (as compared with placebo). A meta-anaylsis published in the British Journal of Clinical Pharmacology states, “Traditionally red ginseng has been used to restore and enhance normal well-being, and is often referred to as an adaptogenic….Possible mechanisms of action of red ginseng include hormonal effects similar to those of testosterone. Others have postulated that red ginseng might induce relaxation of the smooth muscles.”  (5)

Abstract | Full Text PDF | PubMed | Scopus (105) | Google ScholarSee all References Aspirin and β-blocker use have been suggested to decrease the risk of cardiovascular events with sexual activity, although their benefit has not been proved definitively.79x79Kimmel, SE. Sex and myocardial infarction: an epidemiologic perspective. Am J Cardiol. 2000; 86: 10F–13F

Impotence, or erectile dysfunction (ED), is the inability for a man to sustain an erection long enough for normal, satisfying sexual intercourse.  To understand the underlying causes of impotence, it helps to know the basics about how an erection develops, along with potential problems that get in the way. Erections begin in the brain with a thought related to sexual desire. Then a chemical message travels from the brain to the penis. Blood flow to the penis increases as blood vessels leading to the reproductive system relax and allow for increased circulation.
Crossref | PubMed | Scopus (539) | Google ScholarSee all References The MMAS found the total prevalence of minimal to severe ED to be 52% and estimated that more than 617,000 new cases were expected to occur annually in the United States.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

De Berardis et al.6 assessed general HRQOL in 1,460 men with type 2 diabetes in Italy. Within the cohort, 615 men reported that they never experienced ED, 346 stated that they occasionally had ED, and 449 stated that they frequently had ED. They then compared general HRQOL among these three groups. In the univariate analysis, they found that degree of ED negatively correlated with general HRQOL scores in all eight domains of the Short Form 36 (SF-36) health survey questionnaire. In the multivariate analysis, ED was not independently associated with physical function, bodily pain, or role limitations due to physical problem scores but was independently associated with general HRQOL outcomes in the domains of general health (P = 0.004), role limitations due to emotional problems (P = 0.001), vitality (P = 0.001), social functioning (P = 0.01), and overall mental health (P = 0.002). Another study examining the effect of ED on quality of life in hemodialysis patients, more than half of whom had diabetes, also noted an independent, negative effect of ED on the emotional domains of general HRQOL.39
Diuretics: Also called water pills, this medication is a common treatment for reducing blood pressure. They work by getting rid of unnecessary water and salt in the urine. This essentially helps lower blood pressure and can make it easier for the heart to pump blood. Unfortunately, diuretics can reduce the blood flow to the penis, making erections difficult to achieve. Zinc levels have been known to diminish due to diuretic use, which may lead to a decreased production of overall testosterone.
Sildenafil should be taken 1–2 h before intercourse. It is important to tell patients that the drug’s effectiveness requires sexual stimulation. One patient in our clinic recently complained that he had no effect from taking sildenafil. It was later discovered that he took the pill and then sat on his couch and read a book about how to grow tomatoes!
Side effects of sildenafil are similar to those from taking niacin or any vasodilator, namely, headaches, lightheadedness, dizziness, and flushing. Some individuals experience a bluish tinge of their cornea, which makes them feel as if they are wearing light blue–tinted sunglasses. This effect can last for several hours. Syncope and myocardial infarction, the most serious side effects, are seen in men who are also taking nitrates for coronary heart disease. Sildenafil also has adverse effects in people with hypertrophic cardiomyopathy because a decrease in preload and after load in the cardiac output can increase the outflow obstruction, culminating in an unstable hemodynamic state.
The 12-week study of 164 men, all with hypertension, was divided into 2 groups of 82, one group with sexual dysfunction, the other group reported normal sexual functioning. Both groups took losartan in dosages of 50 to 100 milligrams daily for the 12 weeks of the study. In the group of men with sexual dysfunction, 88 percent reported improvement in at least one area of sexual function and 73.7% reported an improved quality of life.
What comes after an ED diagnosis in diabetic patients? Often, Dr. Eid will instantly refer these men to a cardiologist. “If a patient has diabetes and is newly diagnosed, a significant portion of these men are going to develop coronary artery disease in the next 2-3 years,” he said. “One of the things we do is recommend is that they see a cardiologist and perhaps have a stress test or some sort of evaluation.”
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
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
The aetiology of predominantly psychogenic ED is multifactorial, and components may include psychiatric disorders (especially depression), interpersonal problems with the sexual partner or misconceptions about normal sexual activity. Identifying and getting treatment for those patients with psychogenic causes of ED such as depression that may also increase CVD risk is also important.
• Blood Vessels: Diabetes damages blood vessels, especially the smallest blood vessels such as those in the penis. Diabetes can also cause heart disease and other circulatory problems. Proper blood flow is absolutely crucial to achieving erection. “Erection is a hydraulic phenomenon that occurs involuntarily,” says Arturo Rolla, MD, of Harvard University School of Medicine. “Nobody can will an erection!” Anything that limits or impairs blood flow can interfere with the ability to achieve an erection, no matter how strong one’s sexual desire.