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

Abstract | Full Text | Full Text PDF | PubMed | Scopus (395) | Google ScholarSee all References The maximum decrease in blood pressure level was noted at 1 hour after the oral dose was taken and was correlated with peak plasma levels. The blood pressure level in these patients returned to baseline within 4 hours.56x56Wallis, RM, Corbin, JD, Francis, SH, and Ellis, P. Tissue distribution of phosphodiesterase families and the effects of sildenafil on tissue cyclic nucleotides, platelet function, and the contractile responses of trabeculae carneae and aortic rings in vitro. Am J Cardiol. 1999; 83: 3C–12C
Most cases of sexual dysfunction are related to a physical cause. The most common causes are diabetes, heart disease, neurological trauma or disease, and side effects of medications. Stress and anxiety can also contribute to impotence. While most of the focus has been on men with erectile dysfunction, a number of women also suffer from this disorder.
Figure. Progression of atherosclerosis. Endothelial dysfunction occurs early in atherosclerosis and prevents blood vessels from dilating properly. When the blood vessels that supply the penis are not able to dilate during sexual stimulation because of endothelial dysfunction, the penis cannot fill with blood, and the man develops erectile dysfunction. As atherosclerosis progresses, plaques build up in blood vessels and blood flow is slowed, further worsening erectile function. A heart attack occurs when an atherosclerotic plaque in a coronary artery ruptures, a blood clot forms over the plaque, and blood flow to the heart muscle is completely blocked. Atherosclerotic risk factors (black arrows) worsen cardiovascular health; modification of these risk factors (red arrows) improves cardiovascular health.

The vascular endothelium has an important role in angiogenesis and vascular repair by producing regulatory substances, including NO, prostaglandin, endothelins, prostacyclin and angiotensin II. These regulatory factors regulate the blood flow to the penis by controlling smooth muscle contractility and subsequent vasoconstriction and vasodilatation. Generally, in erectile tissue, increased blood flow through the cavernosal artery increases shear stress and produces NO, which further relaxes the vascular smooth muscles and increases blood flow in the corpora cavernosa.54 These events cause penile erection. However, in ED, endothelial NO synthesis is reduced and there is increased endothelial cell death (Figure 2).55
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.
Cardiovascular disease and erectile dysfunction (ED) are closely interrelated disease processes. Erectile dysfunction reportedly affects 10 million to 20 million men in the United States and more than 100 million men worldwide. Each year, about 500,000 persons in the United States survive a myocardial infarction, and an estimated 11 million have existing cardiovascular disease, making the issue of sexual function and cardiac disease relevant to many patients. We explore the relationship between ED and the presence of cardiovascular disease in the general population. We also review the prevalence and pathophysiological associations of ED and cardiovascular disease. The risks of sexual activity for patients with cardiovascular disease are discussed, as are prevention and treatment strategies for ED in this patient population.
Crossref | PubMed | Scopus (42) | Google ScholarSee all References Apomorphine does not appear to have any notable cardiovascular adverse effects and has been used successfully in Europe. However, apomorphine use has been associated with other unpleasant adverse effects such as nausea and emesis, and the drug has not been approved by the US Food and Drug Administration (FDA) for use in the United States.
And diabetes affects more than the blood system. “Diabetes also results in nerve dysfunction and, in the penile shaft, [eventually] the muscle starts to atrophy and is replaced by scar tissue or collagen rather than smooth muscle. That’s the ultimate end result in men,” explains urologist Ajay Nehra, MD, professor of urology at the Mayo Clinic in Rochester, Minn. That scenario — damage to all the tissues that support your penis — is what could happen if you do not get and keep your diabetes under control.

Keep your stress level down. Stress can interfere with sexual arousal and your ability to get an erection. Exercise, meditation, and setting aside time to do the things that you enjoy can help to keep your stress levels down and lessen your risk of ED. If you’re developing symptoms of anxiety or depression, consult your doctor. They may be able to refer you to a therapist who can help you work through anything that is causing you stress.
Get your diabetes under control. According to Dr. Nehra, the most important number you need to stay on top of is your A1C, which is a blood test that lets you know how well your blood sugar has been controlled for the past few months. Lifestyle changes can help and so can medications. Diabetes medications do not add to your risk for erectile dysfunction, says Nehra.
Crossref | PubMed | Google ScholarSee all References In study patients taking these medications compared with controls, significant decreases in total cholesterol and low-density lipoprotein cholesterol levels were found, as well as significant increases in length of maximal tumescence per nocturnal penile tumescence testing at 2 weeks. Hypoglycemia secondary to the use of insulin or hypoglycemic agents may result in ED or orgasmic dysfunction.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
PubMed | Google ScholarSee all References As with sildenafil, use of nitrate or NO-donor medications is contraindicated while taking tadalafil because of the potential for marked hypotensive interactions.74x74Gresser, U and Gleiter, CH. Erectile dysfunction: comparison of efficacy and side effects of the PDE-5 inhibitors sildenafil, vardenafil and tadalafil—review of the literature. Eur J Med Res. 2002; 7: 435–446
Overall, sildenafil appears to be relatively safe and effective for treatment of ED in men with stable cardiovascular disease who are not taking NO-donor medications. In a study of 105 men with ED and known or likely coronary artery disease, patients underwent symptom-limited supine bicycle echocardiography 2 times after receiving either sildenafil or placebo.63x63Arruda-Olson, AM, Mahoney, DW, Nehra, A, Leckel, M, and Pellikka, PA. Cardiovascular effects of sildenafil during exercise in men with known or probable coronary artery disease: a randomized crossover trial. JAMA. 2002; 287: 719–725
Before a man concludes that oral drugs don’t work for him, he should have his testosterone levels checked to rule out hormone deficiency as the cause of (or as a contributor to) his sexual dysfunction. Other symptoms of low testosterone include a low sex drive and infertility. Checking testosterone levels requires a blood test. If a man’s levels of testosterone are decreased or at the lower end of normal, his doctor may prescribe supplemental testosterone therapy, either as testosterone injections or testosterone gel, which is applied daily to the skin. In some cases, testosterone therapy alone can resolve sexual dysfunction, or it can be combined with the use of oral erectile dysfunction drugs.
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