Pharmacotherapy for erectile dysfunction

Erectile dysfunction (ED) is defined as the consistent inability to obtain or maintain an erection for satisfactory sexual relations. An estimated 20- 30 million men suffer from some degree of sexual dysfunction. The past 20 y ears of research on erectile physiology have increased our understanding of the biochemical factors and intracellular mechanisms responsible for corpu s cavernosal smooth muscle contraction and relaxation, and revealed that ED is predominantly a disease of vascular origin. Since the advent of sildena fil (Viagra(R)), there has been a resurgence of interest in ED, and an incr ease in patients presenting with this disease. A thorough knowledge of the physiology of erection is essential for future pharmacological innovations in the field of male ED.