Erectile dysfunction

Drug Store News,  Feb 15, 1999  by Carol Dickson McKee

• E-mail
• Print
• Link

Carol Dickson McKee, Pharm.D. Independent Clinical Consultant and Adjunct Associate Professor; Albany College of Pharmacy, Albany, N.Y. Program # 401-000-99-002-H0l

Goal

This article will provide the pharmacist with an understanding of erectile dysfunction, its common causes and available pharmacological and non-pharmacological treatments.

Objectives

Upon completion of this program, the pharmacist should be able to:

1. Identify the general steps involved in the "normal" male sexual response.

2. List the two general causes of erectile dysfunction and give examples of each.

3. Identify the medications most likely to cause erectile dysfunction.

4. Identify those patients who should not take sildenafil (Viagra(R)) and provide counseling information to the sildenafil patient.

5. List other pharmacological and non-pharmacological means of treating erectile dysfunction.

Introduction

Erectile dysfunction is a relatively common [concern.sup.1], especially among men with chronic diseases, such as diabetes, or those taking certain medications (Table [1.sup.2-5]). Though the incidence of erectile dysfunction increases with age, it is not an inevitable consequence of [aging.sup.6]. Older men are more likely than younger ones to have chronic diseases and to take multiple medications, but sexuality itself does not have an expiration date.

In order to avoid unnecessary treatment or delay in diagnosis of other significant problems, such as prostate cancer, treatment of erectile dysfunction should not be initiated without thorough medical histories and physical examination. Though a number of different treatment options remain available, recent attention has centered on oral sildenafil (Viagra). Sildenafil is not, however, appropriate for everyone, and the occurrence of fatal drug interactions underscores the need for pharmacists to actively educate other healthcare professionals, patients and patients' sexual partners.

Erectile dysfunction is a couple's concern and can profoundly affect the quality of life of both the patient and his partner, so it is essential to involve both partners in consultations and education. Counseling on erectile and other types of sexual dysfunction may also be reimbursable; some third parties cover such treatments, and couples are frequently willing to pay cash for any part not covered by [insurance.sup.7-9]. The demand for knowledgeable, sensitive counseling from pharmacists is likely to increase as the baby-boomer generation ages, develops chronic diseases and takes more medications.

The Concern

Just what is "normal" male sexual [response.sup.(10)(11)]?

William Masters and Virginia Johnson divided the sexual response cycle into four phases: Excitement or arousal, plateau, orgasm and resolution. During the excitement or arousal phase, pelvic engorgement and erection occur in males, -accompanied by increases in muscle tension, heart and respiratory rates and blood pressure. These effects can persist for minutes to hours, through the plateau phase. Orgasm consists of rhythmic contractions of pelvic voluntary and involuntary musculature and may result in ejaculation of semen. During the resolution phase, muscle tension diminishes gradually, and relaxation and drowsiness commonly ensue. Dilation of blood vessels drains pelvic and genital engorgement.

A refractory period follows ejaculation, during which males have difficulty attaining another erection, reaching orgasm and ejaculating. The duration of the refractory period varies widely from man to man, and even within the same man at different times, and it generally increases with age.

How does an erection normally occur?

The body of the penis consists of two long, parallel cylindrical or tubular bodies, the corpora cavernosa, which contain thousands of tiny sacs; each sac is surrounded by smooth muscle. When the penis is flaccid or relaxed, the tone of these muscles around the sacs is increased, which keeps the sacs deflated.

Arousal involves nervous stimulation, which releases prostaglandins, nitric oxide and other substances into the bloodstream that relax these muscles, facilitating blood flow into and engorgement of the sacs. The cavernosa is encircled by a tough, rather inelastic membrane called the tunica. Veins beneath the tunica usually drain blood from the penis. As the cavernosa fill and expand against the rigid tunica, these veins are squeezed closed, keeping the sacs filled or engorged with blood, and resulting in an erection. A "successful" erection thus requires adequate blood supply, hormonal interaction, nerve function and mental or psychogenic status. A change in any one of these may precipitate erectile dysfunction.

What exactly is meant by erectile [dysfunction.sup.(1)(5)]?

"Erectile dysfunction" occurs to varying degrees, but is generally considered to mean the inability of the male to obtain or maintain an erection sufficient for sexual intercourse and ejaculation. Impotency or impotence are sometimes used as synonyms for erectile dysfunction, but since these terms are likely to be more "emotionally charged," erectile dysfunction is generally preferred.