ERECTILE DYSFUNCTION (ED)

Erectile dysfunction (ED) is the inability of the penis to become sufficiently rigid to engage in and complete sexual intercourse. In the great majority of instances ED is not a disease but a symptom of an underlying problem. Estimates are that 15 million to 30 million American men suffer from ED. Public awareness of ED has increased significantly with the introduction of sildenafil citrate (Viagra), the first successful oral therapy for ED. Other therapies existed prior to Viagra but they were invasive or awkward to administer in sexual situations. One of the great secondary benefits wrought by the introduction of oral therapies is that they called public attention to the problem and dispelled the myth that the majority of ED was psychological. There are now three oral therapies and others in trials.

Urologists at Mayo Clinic are conducting ongoing research to find causes and solutions for this condition. Research indicates that as many as 75 percent of all ED cases result from medical problems, usually related to the vascular (blood supply) system in the penis. Vascular problems that cause ED may be related to high cholesterol, diabetes, smoking, surgery or medication.

Mayo Clinic researchers interested in ED have focused in several areas. The following are summaries of recent and current areas of research in ED.

• The physiologic mechanisms and chemical processes that medicate smooth muscle relaxation, and penile erection as the end result of smooth muscle relaxation.
• The association between smoking and erectile dysfunction.
• The risks of sexual activity for patients with cardiovascular disease, specifically, the relationship between ED and the presence of cardiovascular disease, and the prevalence of pathophysiological factors of ED and cardiovascular disease.
• The relationship (if any) between lower urinary tract symptoms and sexual dysfunction.
• The effect of sildenafil citrate (Viagra) on the relationship between changes in systemic blood pressure and coronary blood flow.
• Peyronie's disease is a medical condition characterized by the development of a lump on the shaft of the penis. This lump is a scar (plaque) that forms on the lining (tunica) of the erectile body (corpus cavernosum) and is believed to be the result of injury to the penis. Urology researchers are investigating causes and current hypotheses on the origin of Peyronie's disease other than microvascular trauma and abnormal wound healing, including the possibility of genetic predisposition for Peyronie's disease.