Male Sexual Function: A Guide to Clinical Management (Current Clinical Urology)

From The New England Journal of Medicine

"A man shall cleave unto his wife: and they shall be one flesh" (Genesis 2:24) is the unambiguous biblical directive to married men: participate in and enjoy sexual intercourse. Those who could not do so were considered to lack power -- to be "impotent" -- a distinctly undesirable trait and a sign of weakness in a man, particularly a man considered to be a leader. Our forefathers knew this. When King David, the singer of psalms and slayer of Goliath, was dying, they called upon Abishag, a young Shunammite virgin, to attempt to restore his health. "And the damsel was very fair, and cherished the king, and ministered to him: but the king knew her not" (1 Kings 1:4); once she confirmed his impotence, David was through as a leader, and he was replaced.
Thousands of years later, the problem of impotence was approached in a different way by Freud, who blamed male sexual dysfunction on emotional problems -- psychogenic impotence -- but psychotherapeutic intervention proved to be largely ineffective. Urologists were next in line. They attributed impotence to inadequate penile stiffening, devised penile prostheses, and discovered that papaverine and, more recently, alprostadil caused the penis to become engorged with blood and created an erection when injected directly into the corpora cavernosa. But penile pain was a deterrent to widespread acceptance of this treatment.
The recent decision to expunge the word "impotence" from the medical lexicon and replace it with "erectile dysfunction," or "ED," was intended to make it easier for men to talk about their sexual problems. But solving the mystery of the biochemical mechanism of penile erection was the pivotal advance. We now know the fundamentals: first, during sexual stimulation, the nitric oxide cascade generates the high levels of intracavernosal cyclic GMP needed for blood to be shunted into the cavernosal sinusoids to initiate and maintain an erection (tumescence); second, a decline in cyclic GMP mediated by phosphodiesterase type 5 causes the normal postcoital loss of erection (detumescence). This breakthrough rearranged the landscape of erectile dysfunction, for it led to the discovery and development of the phosphodiesterase type 5 inhibitor sildenafil, which has dramatically alleviated the plight of men with erectile dysfunction.
In editing Male Sexual Function, Mulcahy has taken note of this important development, but almost as an afterthought. The brief, enlightening chapter by Padma-Nathan and Giuliano extensively reviews intracavernosal physiology and the role of inhibitors of phosphodiesterase type 5 in stabilizing erectile function by maintaining the level of intracavernosal cyclic GMP. The authors also review criteria for establishing the effectiveness of sildenafil and alert readers to the newer phosphodiesterase type 5 inhibitors, such as tadalafil and vardenafil, currently submitted for approval by the Food and Drug Administration (FDA). Padma-Nathan and Giuliano explain why the FDA rejected apomorphine, a centrally active agent that is effective in inducing erections. Unfortunately, apomorphine had an unacceptably high rate of adverse effects. Alas, only 22 pages of the nearly 400-page book are devoted to this important advance in our understanding of male sexual physiology.
The bulk of the book will be of interest primarily to urologists. There are chapters on penile implants and complications of penile-implant surgery, Peyronie's disease and its treatment, use of nerve-sparing surgical techniques to prevent erectile dysfunction after radical prostatectomy, and the management of priapism. The contributing authors are distinguished urologists at the forefront of research on the treatment of erectile dysfunction. But urologists may not remain at the forefront; on page 217, we learn that "the majority of [sildenafil] prescriptions have been written by primary care physicians (55-60%), non-urology specialists (21-25%), particul