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, vol. 44 (pg. 360-364)https://doi.org/10.1016/S0302-2838(03)00305-1
Some blood pressure medicines can also cause erectile dysfunction. Thiazide diuretics and beta-blockers are most likely to cause problems, but this is not a common effect of these medicines and will not happen to everyone. If you are taking either of these medicines and are worried about erectile dysfunction, your GP may be able to change your medicines.
Evaluation of functional capacity is the mainstay for the management of patients with ED.30 However, it should be kept in mind that in men with heart failure sexual activity may affect the heart differently from physical activity of similar METS due to differences in psychological anticipation and sympathetic activation.30,49 Cardiac echocardiography may offer valuable information for left ventricular performance and valvular function. For risk categories of heart failure patients and their management, please refer to Table 3 and Figure 5.
Penile erection is largely a vascular process, and the penile endothelium and smooth muscle tissue are very sensitive to functional and structural changes. Vasculogenic ED results from an impairment of endothelial dependent or independent smooth muscle relaxation (functional vascular ED, initial stages), occlusion of the cavernosal arteries by atherosclerosis (structural vascular ED, late stages), or a combination of these.3 Current data support a complex interplay between endothelial dysfunction, subclinical inflammation, and androgen deficiency (Figure 1). The relationship between ED and CAD at the clinical level is supported by this common pathophysiological basis. The ‘artery size’ hypothesis explains why patients with CAD frequently report ED before CAD detection.10 According to this hypothesis, for a given atherosclerotic burden, the smaller penile arteries suffer obstruction earlier than the larger coronary arteries (Figure 2). The same concept holds also true in the case of non-obstructing atherosclerosis: since the smaller penile artery have a greater endothelial surface and erection requires a large degree of vasodilation to occur when compared with arteries in other organs, the same degree of endothelial dysfunction will be symptomatic in these smaller vessels but subclinical in the larger ones (i.e. coronaries). In the same context, accelerated arterial ageing (as indicated by increased arterial stiffening that also affects large arteries of ED patients) may be a common background.11,12 Erectile dysfunction is associated with an incremental inflammatory and endothelial-pro-thrombotic activation.13 Interestingly, this activation is equal to that found in CAD patients with no ED, while when these two conditions are combined the burden is additive. Androgen deficiency may be also implicated in the common pathogenetic pathways of ED and CVD; however, this warrants further substantiation.2
Abstract | Full Text | Full Text PDF | PubMed | Scopus (56) | Google ScholarSee all References Cardiologists use METs of oxygen consumption to compare the energy expenditure of different forms of activity.51x51DeBusk, R, Drory, Y, Goldstein, I et al. Management of sexual dysfunction in patients with cardiovascular disease: recommendations of the Princeton Consensus Panel. Am J Cardiol. 2000; 86: 62F–68F
Crossref | PubMed | Scopus (335) | Google ScholarSee all References Glycemia, as measured by glycosylated hemoglobin, also has been associated with the risk of developing ED in diabetic patients.21x21Klein, R, Klein, BE, Lee, KE, Moss, SE, and Cruickshanks, KJ. Prevalence of self-reported erectile dysfunction in people with long-term IDDM. Diabetes Care. 1996; 19: 135–141
In the past 6 years, the FDA has approved three oral agents for the treatment of ED: sildenafil, vardenafil, and tadalafil. All three are phosphodiesterase type 5 (PDE-5) inhibitors and work by potentiating the effect of nitric oxide in the penis. In particular, they block the hydrolysis of cyclic guanosine monophosphate to guanosine 5'-monophosphate, thus enhancing nitric oxide–mediated smooth muscle relaxation, increasing blood flow to the penis and facilitating erection.
Penile prosthesis is a viable option for men who cannot use sildenafil and who find the injections or vacuum erection therapy distasteful. A non-adjustable semi-rigid prosthesis is easy to insert and has no postoperative mechanical problems. The inflatable prosthesis has a pump that is put in the testicular sac for on-demand inflation and deflation. Future versions will have a remote control device similar to a garage-door opener.
Penile vibratory stimulator is a battery operated device with oscillating discs that can provide excitation of afferent penile nerves at various regulated frequency and amplitudes. PVS has been utilised to activate the ejaculatory reflex for patients with spinal cord injury above T10 seeking to collect retrogradely ejaculated semen in fertility treatment (10). The Viberect is a vibratory stimulation handheld device approved by FDA for treatment of ED. It is clamp-shaped with two oscillating discs facing each other near the tips, and the glans penis is placed between the two oscillating discs to receive concurrent dorsal and ventral stimulation at adjustable frequencies and amplitudes.
Phosphodiesterase Inhibitors. The cornerstone of first-line therapy is the PDE-5 inhibitor. No other class of oral agents approaches the efficacy of PDE-5 inhibitors. Yohimbine, trazodone, phentolamine, L-arginine, and OTC herbal remedies have been used with very limited success. The superiority of yohimbine over placebo in the treatment of organic ED is a matter of dispute.9 A recent trazodone study failed to detect any difference between trazodone and placebo on sexual function.10 Oral phentolamine, although available in Mexico, has not been approved by the US FDA for the treatment of ED. Apomorphine, a central dopaminergic receptor drug, has recently been voluntarily withdrawn from FDA consideration for the treatment of ED. The efficacy of ginkgo biloba and Korean red ginseng has yet to be demonstrated by randomized, placebo-controlled trials.
Gazzaruso C, Solerte SB, Pujia A, Coppola A, Vezzoli M, Salvucci F, Valenti C, Giustina A, Garzaniti A. Erectile dysfunction as a predictor of cardiovascular events and death in diabetic patients with angiographically proven asymptomatic coronary artery disease: a potential protective role for statins and 5-phosphodiesterase inhibitors, J Am Coll Cardiol , 2008, vol. 51 (pg. 2040-2044)https://doi.org/10.1016/j.jacc.2007.10.069
Crossref | PubMed | Scopus (71) | Google ScholarSee all References However, a double-blind, placebo-controlled study of 22 middle-aged men with hypercholesterolemia treated for 6 weeks with pravastatin or lovastatin showed improved erectile function with both medications.54x54Kostis, JB, Rosen, RC, and Wilson, AC. Central nervous system effects of HMG CoA reductase inhibitors: lovastatin and pravastatin on sleep and cognitive performance in patients with hypercholesterolemia. J Clin Pharmacol. 1994; 34: 989–996
When counseling diabetic men who are considering a PDE-5 inhibitor for ED, it is important to set realistic expectations and explain that studies document that all three agents are less effective in diabetic patients than in the general population of men with ED.45–49 For additional information, readers are referred to the excellent review of the use of PDE-5 inhibitors in diabetic men by Vickers and Satyanarayana.50
Crossref | PubMed | Google ScholarSee all References Risk factors for cardiovascular disease include diabetes mellitus, obesity, physical inactivity, hyperlipidemia, tobacco use, and hypertension. Often, the relative risk of each of these factors in the development of ED is difficult to assess because many patients with ED and cardiovascular disease have more than 1 risk factor. Another important consideration is the effect of cardiac disease itself on erectile function. A history of a prior myocardial infarction was not found to be a significant independent risk factor for ED in a study comparing sexual function in 50 patients who had a prior myocardial infarction with a control group of 50 patients.14x14Dhabuwala, CB, Kumar, A, and Pierce, JM. Myocardial infarction and its influence on male sexual function. Arch Sex Behav. 1986; 15: 499–504
A component of the increased risk conferred by ED could be testosterone deficiency.24 Low testosterone leads to increased levels of total and LDL cholesterol, as well as to increased production of pro-inflammatory markers and mediators.25 Endothelial dysfunction and increased arterial wall thickness, stiffening, and calcification also ensue. On this basis it has been hypothesized that chronically lowered testosterone may increase CVD risk. Indeed, androgen deficiency has emerged as a predictor of CV events, as well as of all-cause and CV mortality, both in the general population and in patients with CV risk factors, with hypertension, with established CVD, and with ED.26 Viewed from the opposite angle, higher serum testosterone showed a protective role for CV events in elderly men.27 A 2010 meta-analysis limited to studies in middle-aged men found no association between total testosterone (TT) levels and CVD risk.28 However, a more recent meta-analysis involving a larger number of studies identified significant associations between androgen deficiency and increased risk of CVD and CVD mortality.29 It should be stressed, however, that the nature of these studies cannot prove causality. The possibility that low testosterone may be an epiphenomenon, marking poor general health rather than modulating CVD risk per se has to be explored.
Oral medicines: The best known ED medications are the Big Three: Viagra (sildenafil citrate, made by Pfizer, Inc.), Levitra (vardenafil HCl, made by Bayer and GlaxoSmithKline), and Cialis (tadalafil, made by Eli Lilly). The three are chemically very similar, and all have proven very effective. Because they are effective, convenient, and relatively inexpensive (about nine dollars per pill), these medicines have become the treatment of choice for most men experiencing ED.
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.
Table 3 is a suggested algorithm for the assessment of patients and their further categorization and handling. There are parts of investigation that are common for patients both with and without CVD, while additional elements of investigation are helpful in categorizing the patient without CVD to the appropriate risk category. Determination of exercise ability and stress testing is crucial to the assessment (see also below ‘Exercise ability: the risk of sexual activity’). Patients without established CVD or diabetes should be evaluated for their risk of future events according to risk scores (SCORE or Framingham). Patients with established CVD or diabetes are by default considered at increased risk. Patients with adequate exercise ability or a negative stress test can initiate or resume sexual activity and begin treatment for ED. In patients with a positive stress test or in high-risk patients, sexual activity should be deferred until the cardiac condition has been treated and stabilized. In all cases, patient follow-up and reassessment is recommended.
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Neelima V. Chu, MD, is an endocrinology fellow in the Division of Endocrinology and Metabolism at the University of California, San Diego. Steven V. Edelman, MD, is an associate professor of medicine in the Division of Endocrinology and Metabolism at the University of California, San Diego, and the Division of Endocrinology and Metabolism at the San Diego VA Health Care Systems in San Diego. He is founder and director of Taking Control of Your Diabetes, a nonprofit organization, and an associate editor of Clinical Diabetes.
Towards this direction, several sufficiently powered studies have demonstrated a higher incidence of erectile dysfunction in patients with coronary artery disease, either asymptomatic or overt. At the same time, patients with erectile dysfunction are more prone to have established coronary artery stenosis of more than 50% and consequently evident CV disease. This is in conformity with the “artery size hypothesis” according to which smaller arteries (e.g., penile arteries) are the first to undergo a vascular lesion prior to the larger ones (e.g., coronary arteries). Moreover, in such patients erectile dysfunction is connected to the number of occluded vessels and more interestingly occurs over three years before coronary artery disease becomes apparent[76-80].
Erectile dysfunction (ED) is highly prevalent affecting at least 50 % of men with diabetes mellitus (DM). DM may cause ED through a number of pathophysiological pathways. These include neuropathy, endothelial dysfunction, cavernosal smooth muscle structural/functional changes, and hormonal changes. Lifestyle changes, diabetes control, and treatment of hypogonadism are important as the first step in ED management since there is no curative treatment for ED. Phosphodiesterase type 5 inhibitors (PDE5i) are the first-line treatment option. Intracavernous administration of vasoactive drugs is commonly used as a second-line medical treatment when PDE5i have failed. Alprostadil is the most widely used drug in this second-line setting. The combination of papaverine, phentolamine, and alprostadil represents the most efficacious intracavernous pharmacologic treatment option that may save non-responders to alprostadil. Penile prosthesis implantation can be considered in treatment refractory cases, with excellent functional and safety results in the properly informed patients.
Following the breakthrough in ED treatment using PDE5-inhibitors, Western medicine has now moved on to a new frontier of regenerative medicine, with stem cell and gene therapy leading the way (25). There is a practical need for novel therapy as a significant portion of diabetic or post-prostatectomy ED patients do not respond to oral pharmacotherapy. To date, stem cells derived from different sites including adipose tissue-derived stem cells, bone marrow mesenchymal stem cells and muscle-derived stem cells have been investigated using animal models for ED, to study their effects on neural, vascular, endothelial or smooth muscle regeneration (25,26).
There are a number of reasons a man may not achieve the desired result from an oral erectile dysfunction drug. In some cases, a man may experience drug side effects severe enough to outweigh any potential benefit of taking the drug. Possible side effects of these drugs include headache, facial flushing, nasal congestion, and transient abnormal vision. (In October 2007, the FDA added a warning about sudden hearing loss to the package labels of oral erectile dysfunction drugs. While it’s not absolutely clear that the drugs can cause sudden hearing loss, a number of cases have been reported in men within hours or days of taking one of the drugs.)