Microvascular Complications in Diabetic Erectile Dysfunction

Advances in the management of erectile dysfunction (ED) and its adverse effects on the quality of life of men and their partners have encouraged researchers to look for new solutions for treating and curing ED. The introduction of phosphodiesterase type 5 inhibitors to treat ED in 1998 was revolutionary in that it heralded the onset of a new era of effective and safe treatment for restoring male sexual function. Today, PDE5 inhibitors are used as first-line therapy for the management of ED irrespective of its etiology. Despite the fact that millions of men with ED worldwide have been treated successfully with these drugs, several questions regarding their efficacy and safety and the high dropout rate in men to whom these medications are prescribed remain unanswered. This is especially evident in diabetes because the frequency of ED in men with diabetes is higher than that of the general population. In fact, the frequency of ED in diabetic men has been reported to be as high as 75% in men with longstanding disease (1–3). In contrast to the high efficacy rate of PDE5 inhibitors in the general population (70–89%), just over 50% of diabetic men with ED respond favorably to these drugs (4). Impaired neural and penile vascular functions are believed to be the main reasons for the high incidence of ED in men with diabetes, and the underlying causes of this drug resistance are not fully understood. Recent data indicate that PDE5 inhibitors have beneficial effects in other chronic diseases. Sildenafil has been approved recently for the treatment of idiopathic pulmonary hypertension (5). Lately, several reports have suggested that PDE5 inhibitors may improve arterial function (6–9). Moreover, improvement of lower urinary tract symptoms in patients with benign prostatic hyperplasia has also been reported (10). Finally, the results of research in the basic sciences and clinical studies have yielded promising therapeutic results regarding the continual use of PDE5 inhibitors to treat a variety of diseases including ED.