Normal male sexual function requires a complex interaction of vascular, neurological, hormonal, and psychological systems. The initial obligatory event is acquisition and maintenance of an erect penis, which is a vascular phenomenon. Normal erections require blood flow into the corpora cavernosae and corpus spongiosum. As the blood accelerates, the pressure within the intracavernosal space increases dramatically to choke off penile venous outflow. This combination of increased intracavernosal blood flow and reduced venous outflow allows a man to acquire and maintain a firm erection.
Three longitudinal studies have estimated incidence rates of ED in men with diabetes. Unfortunately, none of these studies specifically examined men with type 2 disease. In a cohort of 278 diabetic men with type 1 or type 2 diabetes potent at study entry, the proportion of patients reporting ED at 5-year follow-up was 28%.7 A follow-up analysis of the Massachusetts Male Aging Study, a community-based cohort of men between 40 and 70 years of age, found that the incidence of ED in the diabetic men was 51/1,000 population-years.8 This figure was similar to the 68/1,000 person-years crude incidence rate of ED reported in a study of 1,010 men with diabetes.5 However, new studies need to be carried out in well-characterized populations of men with diabetes in order to better determine the incidence of ED and potential effects of interventions to reduce complications.
While a widely held perception is that CVD drugs cause ED, data attest towards the contrary and some agents may be even beneficial.41 Only thiazide diuretics lead clearly to ED, while some older beta-blockers also do so, but the side-effect of ED was very low (∼3%) when the patient was blinded for the drug administration.42 In fact, the vasodilating nebivolol may even improve erectile function.35,43 ACE-inhibitors, angiotensin-receptor blockers, and calcium-channel blockers are reported to have neutral or even a positive effect on erectile function35,41,43 but more evidence is needed. Regarding statins, the largest body of evidence point towards a beneficial effect.44 A negative effect has been reported in high statin doses, possibly related to a potential reduction in serum testosterone levels, but this dose dependency warrants further investigation. In terms of patient management, when ED onset and therapy initiation are linked and a cause-and-effect association is presumed, a short period of drug withdrawal with monitoring for ED resolution for verification may be an option. In patients who developed ED long after the initiation of CV drug treatment, sexual dysfunction is less likely to be drug associated and PDE5 inhibition therapy may be initiated.
The Massachusetts Male Aging Study of 1,290 men, aged 40–70 years, has documented the extraordinarily high prevalence of erectile dysfunction among aging men: 50% of men at 50 years of age, and 70% by age 70 have erectile dysfunction.2 Furthermore, a recent Italian study of men with severe heart disease has uncovered an astounding 93% with erectile dysfunction 24 months before their heart attack or onset of heart disease symptoms.3
Alprostadil self-injection. With this method, you use a fine needle to inject alprostadil (Caverject Impulse, Edex) into the base or side of your penis. In some cases, medications generally used for other conditions are used for penile injections on their own or in combination. Examples include papaverine, alprostadil and phentolamine. Often these combination medications are known as bimix (if two medications are included) or trimix (if three are included).

Men with diabetes tend to develop erectile dysfunction 10 to 15 years earlier than men without diabetes. As men with diabetes age, erectile dysfunction becomes even more common. Above the age of 50, the likelihood of having difficulty with an erection occurs in approximately 50% to 60% of men with diabetes. Above age 70, there is about a 95% likelihood of having some difficulty with erectile dysfunction.