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.
The causes of ED are numerous but generally fall into two categories: organic or psychogenic. The organic causes can be subdivied into five categories: vascular, traumatic/postsurgical, neurological, endocrine-induced, and drug-induced. Examples of the psychogenic causes are depression, performance anxiety, and relationship problems. In people with diabetes, the main risk factors are neuropathy, vascular insufficiency, poor glycemic control, hypertension, low testosterone levels, and possibly a history of smoking.

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.
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.
Admitting to your doctor that you are having trouble achieving an erection can be difficult, but take comfort in the fact that they are not judging you and are there to improve your health and well-being. If you are just beginning a blood pressure treatment regimen and are beginning to experience erectile dysfunction, tell your doctor as soon as you can—they can solve the problem by simply changing the prescription.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Phase 2 and 3 trials reported minimal associated cardiac adverse effects, which occurred in 3% of patients taking sildenafil and in 3.5% of patients receiving placebos.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
PubMed | Google ScholarSee all References In a double-blind, placebo-controlled study, sildenafil was effective in patients with diabetes mellitus.58x58Rendell, MS, Rajfer, J, Wicker, PA, Smith, MD, and Sildenafil Diabetes Study Group. Sildenafil for treatment of erectile dysfunction in men with diabetes: a randomized controlled trial. JAMA. 1999; 281: 421–426
Whereas lifestyle modification is a reasonable initial step when approaching a hypertensive patient with sexual dysfunction, finding the appropriate antihypertensive treatment is usually the next “complicated” move to care for. Several observational and clinical studieshave consistently associated antihypertensive medication with sexual dysfunction[20]. Whether one class of antihypertensive agents is associated exclusively or more with erectile dysfunction compared to another, however, is a difficult puzzle to solve as there are many other factors (comorbid conditions, concomitant medications, personal characteristics) to be taken into account at the same time. In addition, erectile dysfunction has never been studied as the primary end-point before and as a result a definite causative relationship between antihypertensive medication and sexual dysfunction has never been proven.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References During this period, 130 deaths were reported to the US FDA; 41 of these men died or had cardiac arrest within 4 to 5 hours after taking sildenafil, and 27 died or had cardiac arrest either during or immediately after sexual activity. The average age of these men was 64 years. Of the 77 men in this group who died of documented cardiovascular-related events, 41 died of definite or suspected myocardial infarction, 27 died after cardiac arrest, and 6 had symptoms of cardiac disease at the time of death. Sixteen of the men had taken nitroglycerin or organic nitrates in association with sildenafil; another 3 had nitroglycerin in their possession at the time of death. In 48 men, the cause of death was unknown, and another 3 died of cerebrovascular accidents. Overall, it was concluded that sildenafil was not associated with an excess of cardiovascular death.
While Western medicine emphases the link between cardiovascular function and ED, TCM places importance on liver and kidney ailments as causative factor for development of ED. Western medicine involves a step-wise approach by targeting the relevant organ systems to treat various clinical symptoms; but TCM focuses on restoring the balance between various organs to achieve harmony and holistic approach to inner sense (4). The following article reviews our current understanding regarding the philosophical approach, and evaluates the evidence surrounding various ED therapies between mainstream Western medicine and TCM (see Table 1).
The recommended dosage of sildenafil is 50 mg/day, usually taken 1 hour before sexual activity. This dose may be increased to 100 mg or decreased to 25 mg based on side effects.6 PDE5 inhibitors also have a beneficial effect in the treatment of heart failure with reduced ejection fraction as well as pre- and post-capillary pulmonary hypertension. The use of PDE5 inhibitors in the treatment of right heart failure and left ventricular failure associated with combined pre- and post-capillary pulmonary hypertension has been well studied.71,72

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).
One study the authors reviewed measured these changes in middle-aged men with and without coronary artery disease. This study found that the peak heart rate during intercourse was lower than heart rates measured during the patients' normal daily activities. The study participants' peak oxygen consumption levels during intercourse were moderate -- comparable to their oxygen consumption levels during moderate activities such as walking on level ground at 3 to 4 miles per hour, climbing stairs slowly or doing general housework such as vacuuming.

Abstract | Full Text | Full Text PDF | PubMed | Scopus (25) | Google ScholarSee all References Patients with prior cardiac events should be encouraged to enroll in cardiac rehabilitation programs before restarting sexual activity.80x80Muller, JE. Triggering of cardiac events by sexual activity: findings from a case-crossover analysis. Am J Cardiol. 2000; 86: 14F–18F
David F. Penson, MD, MPH, is an associate professor of urology and preventive medicine in the Keck School of Medicine at the University of Southern California, in Los Angeles. Hunter Wessells, MD, is an associate professor of urology at the University of Washington School of Medicine and chief of urology at Harborview Medical Center in Seattle, Wash.
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.
×