Now that we better appreciate the complex sequence of events necessary for erections to occur, it’s no surprise that testosterone alone yields less than perfect results. Erectile dysfunction represents more than just low testosterone, which is just one facet of the spectrum of dysfunctional phenomena that cause sexual dysfunction. Nonetheless, when testosterone is combined with popular drugs like Viagra®, success is enhanced to an even greater degree—orgasmic function improves, along with erectile capacity and libido.20 Testosterone also activates penile nitric oxide; ultrasound studies have demonstrated a 27% increase in arterial blood flow into the penis with testosterone supplementation.23

Erections also require neural input to redirect blood flow into the corpora cavernosae. Psychogenic erections secondary to sexual images or auditory stimuli relay sensual input to the spinal cord at T-11 to L-2. Neural impulses flow to the pelvic vascular bed, redirecting blood flow into the corpora cavernosae. Reflex erections secondary to tactile stimulus to the penis or genital area activate a reflex arc with sacral roots at S2 to S4. Nocturnal erections occur during rapid-eye-movement (REM) sleep and occur 3–4 times nightly. Depressed men rarely experience REM sleep and therefore do not have nocturnal or early-morning erections.
Due to their vasorelaxing effect, administration of PDE-5 inhibitors in hypertensive individuals was initially confronted with great suspicion. A wealth of clinical data however has proven that PDE-5 inhibitors are associated with few side effects and provoke a small and insignificant reduction in blood pressure with minimal heart rate alterations in both normotensive and hypertensive patients as well. As a matter of fact, they can be safely and effectively administered to hypertensive individuals even when they are already taking multiple antihypertensive agents[51-56]. The sole exception to the rule is co-administration with organic nitrates, which is an absolute contraindication due to profound and possibly hazardous hypotension effect[57,58]. Moreover, precaution should be taken when PDE-5 inhibitors are combined with a-blockers where, due to possible orthostatic hypotension effect, lower starting doses should be implemented in the therapeutic regime[59-62].
Characteristics that imply a higher risk is severe ED (SHIM 1–7) and ED duration >3 years.15,30 Vascular and circulating biomarkers may help to characterize further the patient with ED.23 Of the wide array of biomarkers that have been proposed for the assessment of cardiovascular risk in asymptomatic adults,34,35 some have been studied specifically in the context of ED.23Table 4 offers a critical evaluation of these biomarkers. Such tests should be considered as potentially helpful and thus recommended where available, but not mandatory.30 Despite its potent predictive ability recently shown,36 exposure to radiation with coronary artery calcium scoring should be carefully weighed. Although not specific for ED, it might be reasonable to evaluate biomarkers that have been proposed for the intermediate-risk patient such as uric acid, glycated haemoglobin, microalbuminuria, and lipoprotein-associated phospholipase A2.30
To understand what happens in ED, it's helpful to know some anatomical basics. When aroused by either sensory or mental stimuli, the brain sends a signal through the nerves to the penis, causing the muscles there to relax. This opens up space for blood to flow in and engorge the penis. A membrane within the penis traps blood inside to help maintain the erection, which subsides when the penile muscles contract, forcing blood back into the rest of the body. Any number of things can go wrong in this process, leading to erectile dysfunction.
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.
Not surprisingly, they found that diabetic patients rated kidney disease and blindness as the two most important complications of their condition. Diabetic men with ED ranked ED as the third most important complication of diabetes, followed on average in order by foot ulcers, high blood pressure, high cholesterol, migraine headaches, sleeping disorders, and mild indigestion. Diabetic men without ED found ED slightly less important, ranking it behind foot ulcers and high blood pressure, although all three were grouped fairly close together (mean ranks were 4.59, 4.23, and 4.52, respectively). Interestingly, in men both with and without ED, subjects were willing to pay more per month to avoid ED than all other conditions except blindness and kidney disease (mean values for diabetic patients with ED were £50.5, £88.0, and £66.1, respectively). In summary, erectile function is important to diabetic men, and when ED is present, it has a significant negative effect on quality of life.

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.
However, population-based studies of ED in prostate cancer survivors also document that ED has a negative effect on general health. Penson, et al.36 studied HRQOL in 2,306 prostate cancer survivors 2 years after their diagnosis. They noted that men with ED (defined as erections that were insufficient for sexual intercourse) had significantly worse general HRQOL when compared to prostate cancer survivors who were potent. Importantly, this association remained in a multivariate analysis that controlled for 31 other potential confounding variables. Finally, this association was noted in both the physical and mental domains of general quality of life, indicating that ED has a much broader effect on quality of life than one might expect.
In diabetic patients who fail medical management of ED, penile implantation surgery remains a viable therapeutic option. In a recent review of 372 men who underwent implantation of a three-piece inflatable penile implant, 86% reported that the device was still functional 5 years after implantation, and 79% reported that they used the device at least twice monthly.59
For patients who failed oral medical therapy or unable to tolerate the side effects, intracavernosal injection of vasoactive agents can often provide effective alternative. Various vasoactive agents such as alprostadil, papaverine or phentolamine have been used either as single agent or combination agents to potentiate the NO release and cavernosal smooth muscle vasodilation. However, intracavernosal injection therapy has high attrition rate and can be associated pain especially with alprostadil injection (2). The practice of isolating compounds and understanding its pharmacological attributes before using it as a drug therapy has been a strength of Western medicine.

* Low-risk patients include those with complete revascularization (eg, via coronary artery bypass grafting, stenting, or angioplasty), patients with asymptomatic controlled hypertension, those with mild valvular disease, and patients with left ventricular dysfunction/heart failure (NYHA classes I and II) who achieved 5 metabolic equivalents of the task METS without ischemia on recent exercise testing.
Yohimbine is an indole alkaloid derived from the bark of the African yohimbe tree (33). Yohimbine has been noted to treat fatigue, depression, diabetes, and sexual dysfunction. A meta-analysis of seven placebo-controlled trials (34) deemed yohimbine superior to placebo for the treatment of ED with rare adverse events. The proposed mechanism of action (35) is via the inhibition of central alpha-2-adrenergic receptors, decreasing central inhibition of arousal, and increasing penile nerve stimulation resulting in increased NO. Common side effects include headache, sweating, agitation, hypertension and insomnia. Contraindications include patients on tricyclic antidepressants, anti-hypertensives and central nervous system stimulants.
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).
Erections also require neural input to redirect blood flow into the corpora cavernosae. Psychogenic erections secondary to sexual images or auditory stimuli relay sensual input to the spinal cord at T-11 to L-2. Neural impulses flow to the pelvic vascular bed, redirecting blood flow into the corpora cavernosae. Reflex erections secondary to tactile stimulus to the penis or genital area activate a reflex arc with sacral roots at S2 to S4. Nocturnal erections occur during rapid-eye-movement (REM) sleep and occur 3–4 times nightly. Depressed men rarely experience REM sleep and therefore do not have nocturnal or early-morning erections.
Conversely, and of significant clinical importance, is how often patients with ED as their first and sole clinical manifestation suffer from subclinical CAD.17 Previous studies reported a rate of inducible ischaemia by exercise stress testing (EST) in 22% (with a wide range of 5–56%) of ED patients reflecting differences in patient population, risk factors and criteria used for ED and CAD diagnosis. Interestingly, those patients further assessed with coronary angiography had obstructive atherosclerosis in >90% of cases.4,18 In a prospective angiographic study, we documented that 19% of ED patients suffer from clinically silent obstructive CAD.18
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References, 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
ED is a common complication of diabetes that affects patients' quality of life. While the etiology of this complication may be multifactorial in nature, it is clear that it usually has a strong organic component. Because men with diabetes value their erectile function highly, it is important that providers encourage them to maintain good glycemic, blood pressure, and lipid control to minimize their risk of developing this complication.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (328) | Google ScholarSee all References Their mean resting systolic and diastolic blood pressure levels decreased by 6% and 11%, respectively, compared with baseline. These patients also experienced a mild decrease in mean resting right atrial pressure, pulmonary artery pressure, pulmonary artery occlusion pressure, and cardiac output. However, the hemodynamic response to exercise was preserved. Phase 2 and 3 trials showed no difference in the rate of adverse events between sildenafil and placebo in patients being treated with antihypertensive medications. The effects of sildenafil on blood pressure level were similar in patients who were taking antihypertensive medications compared with those who were not. In healthy volunteers, no consistent or significant doserelated electrocardiographic (ECG) changes were noted at 1 and 2 hours after doses of sildenafil ranging from 1.25 to 200 mg.3x3Zusman, RM, Morales, A, Glasser, DB, and Osterloh, IH. Overall cardiovascular profile of sildenafil citrate. Am J Cardiol. 1999; 83: 35C–44C
Even if you do not take blood pressure drugs, you should get your blood pressure checked as high BP also can be a sign of ED. In fact, men with ED are about 38% more likely to have high blood pressure than those without ED, according to a study that examined the medical records of more than 1.9 million men. That is not too surprising, since ED often occurs in men who smoke or are overweight—both of which are common risk factors for high blood pressure.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Rates of severe cardiovascular adverse effects were also similar at 1.7 per 1000 person-years of treatment with sildenafil compared with 1.0 events per 1000 personyears with placebo treatment.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
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.
Combination therapy has proven effective for some men who don’t respond adequately to oral medicines. The idea is to use two drugs with different mechanisms of action for better results. Commonly, sildenafil is used in combination with pellets of alprostadil (synthetic prostaglandin E1) that are inserted into the urethra (the tube in the penis that carries urine from the bladder to the outside of the body). Alprostadil also increases the blood supply to the penis, but by different means.
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