Abstract | Full Text | Full Text PDF | PubMed | Scopus (259) | Google ScholarSee all References Sildenafil should be used with caution in patients with liver dysfunction or renal impairment, as well as in patients taking any medications that inhibit the P-450 pathway such as cimetidine or erythromycin.3x3Zusman, RM, Morales, A, Glasser, DB, and Osterloh, IH. Overall cardiovascular profile of sildenafil citrate. Am J Cardiol. 1999; 83: 35C–44C
Abstract | Full Text | Full Text PDF | PubMed | Scopus (66) | Google ScholarSee all References Risk of arrythmias after sexual intercourse was evaluated in 82 patients with stable coronary artery disease who were monitored with ambulatory ECG after sexual intercourse.81x81Drory, Y, Fisman, EZ, Shapira, Y, and Pines, A. Ventricular arrhythmias during sexual activity in patients with coronary artery disease. Chest. 1996; 109: 922–924
Getting blood glucose under control is a good anti-ED tactic. Men with diabetes and poor blood glucose control are two to five times as likely to have ED as those with good control. One study in a group of men who had had type 1 diabetes for up to 15 years with minor complications found that intensive blood glucose control lowered the risk of ED compared with conventional treatment. A study in men with type 2 diabetes found that lowering A1C (average blood glucose in the past two to three months) below 7 percent and reducing blood pressure through a combination of medication, diet, and exercise improved sexual functioning.
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)
Acupuncture. Though acupuncture has been used to treat male sexual problems for centuries, the scientific evidence to support its use for erectile dysfunction is equivocal at best. In 2009, South Korean scientists conducted a systematic review of studies on acupuncture for ED. They found major design flaws in all of the studies, concluding that "the evidence is insufficient to suggest that acupuncture is an effective intervention for treating ED."
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

Erectile dysfunction usually precedes cardiovascular events by 3 to 5 years. Therefore, sexual function should be incorporated into cardiovascular disease risk assessment for all men. Recently, algorithms for the management of patients with erectile dysfunction according to the risk for sexual activity and future cardiovascular events were proposed[91]. A comprehensive approach to cardiovascular risk reduction (comprising of both lifestyle changes and pharmacological treatment) will result in significant benefits on overall vascular health, including sexual function. Proper sexual counselling will exert beneficial effects on the quality of life of hypertensive patients with erectile dysfunction and will improve adherence to antihypertensive drug therapy[91].
Experimental hyperglycemia may also affect cavernosal smooth muscle cell contractile responses. In experimental diabetes, penile smooth muscle has augmented force responses to vaconstrictors, possibly mediated by changes in expression of protein kinase C and the RhoA-Rho kinase Ca2+-sensitization pathway.32 These changes may promote flaccidity and alter the relaxation responses to nitric oxide. End-stage penile dysfunction may occur as a result of diabetes, with progressive loss of normal cavernosal endothelium and smooth muscle cells from the corpus cavernosum.33 Replacement by fibrotic tissue may lead to complete erectile failure.34
PubMed | Google ScholarSee all References The risk of ED was 1.83 times higher in men with a total cholesterol level greater than 240 mg/dL as opposed to less than 180 mg/dL. Also, an HDL cholesterol level greater than 60 mg/dL was found to be protective against the development of ED. In the MMAS, HDL cholesterol levels were noted to have an inverse relationship with the presence of ED.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
Penile prosthesis implant remains the most effective and permanent treatment for ED. Penile prosthesis implants can be broadly divided into malleable and inflatable prostheses (20). Malleable penile prosthesis, also known as semi-rigid prosthesis, does not allow for (physiological) flaccid state of the penis. The patient can bend the prosthesis upwards for sexual intercourse and downwards for concealment. Although the angle of prosthesis concealment has improved with recent devices, however due to the constant rigid state of the penis, they are still less comfortable compared to their inflatable counterparts, are more likely to cause social embarrassment and associated with higher risk of implant erosions (21). However, malleable prosthesis still has its place for the treatment of ED as these implants are easier to handle, easier to place and would benefit patients with impaired manual dexterity.
Erectile dysfunction (ED) is defined as the inability to achieve or maintain an erection for satisfactory sexual performance. The prevalence of ED has been estimated as nearly 40% of men >40 years of age1 although these figures are contested.2 ED increases in frequency with age and is estimated to affect 15% of men aged 40–50 years, 45% of men in their 60s and 70% of men older than 70 years.3 Successful erection is a complex system involving reflex action (peripheral nerves and spinal cord), the limbic system (psychogenic stimuli) and the release of nitric oxide. Adequate levels of testosterone are required, and hence an intact hypothalamic/pituitary/testicular axis. Hence, ED can result from disease or treatment that produces hormonal deficiency, neurological impairment, problems with penile blood flow, disorders of tissue mechanics, psychological factors or any combination of these.

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In another study, 60 patients underwent stress exercise cardiovascular testing and Doppler ultrasonography for measurement of their cavernosal artery peak systolic velocity (PSV).17x17Kawanishi, Y, Lee, KS, Kimura, K et al. Screening of ischemic heart disease with cavernous artery blood flow in erectile dysfunctional patients. Int J Impot Res. 2001; 13: 100–103
4. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Erectile dysfunction (updated Nov 2015). https://www.niddk.nih.gov/health-information/health-topics/urologic-disease/erectile-dysfunction/Pages/facts.aspx (accessed Nov 2016). myDr myDr provides comprehensive Australian health and medical information, images and tools covering symptoms, diseases, tests, medicines and treatments, and nutrition and fitness.Related ArticlesImpotence causesFind out the physical and psychological causes of impotence, also called erectile dysfunction or ED.Erectile dysfunction: visiting your doctorFind out what questions a doctor may ask when discussing erectile dysfunction (ED, or impotence8 Surprising causes of erectile dysfunctionOccasional erectile dysfunction is not uncommon, but if it's persistent, erectile dysfunction caAdvertisement
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.
Research is mixed on the effectiveness of acupuncture as an erectile dysfunction cure, but one study published in November 2013 in the Journal of Alternative and Complementary Medicine found that acupuncture can be beneficial for men experiencing erectile dysfunction as a side effect of antidepressants, including selective serotonin reuptake inhibitors (SSRIs) and serotonin noradrenaline reuptake inhibitors (SNRIs).
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

Inflatable prostheses are complex mechanical devices that imitate the natural process of erection. Parts are inserted surgically into the penis and scrotum, and activated by squeezing. When erection is no longer desired, a valve on the pump is pressed, and the penis becomes flaccid. Self-contained single-unit prostheses are similar to the inflatable types, but more compact. The entire device is implanted into the penis. When erection is desired, the unit is activated by either squeezing or bending, depending on which of the two types of self-contained prostheses is used.
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
Smoking is an independent risk factor for ED. Tobacco smoking causes direct toxicity to endothelial cells, including decreased eNOS activity, increased adhesion expression and impaired regulation of thrombotic factors.6 A meta-analysis of 19 studies by Tengs and Osgood suggested that 40 % of the impotent men studied were current smokers compared with 28 % who had never smoked.49
Table 1 offers elements for distinction between organic and psychogenic disease.7 Of note is that in cases of organic origin, a psychogenic component may co-exist. The most common organic aetiology of ED is vasculogenic (see below ‘ED and CAD: common pathophysiology’).2,3 Co-existence of vascular disease, advancing age, and the presence of CVD risk factors and metabolic disorders increase the likelihood that ED is of vasculogenic aetiology.
Taking one of these tablets will not automatically produce an erection. Sexual stimulation is needed first to cause the release of nitric oxide from your penile nerves. These medications amplify that signal, allowing some men to function normally. Oral erectile dysfunction medications are not aphrodisiacs, will not cause excitement and are not needed in men who get normal erections.
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
• 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.
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