Sexual Dysfunction

Fred Govier, MD
Chief of Surgery, Virginia Mason Medical Center, Seattle WA
Professor of Urology, University of Washington, Seattle WA

Introduction

Sexual dysfunction in the male is a very common problem that encompasses erectile dysfunction (ED), premature ejaculation, and low libido as its main components. This update will focus primarily on ED, which is the most common form of sexual dysfunction in the American Male. The Sexual Medical Society of North America has defined ED as “the persistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance”. Erectile dysfunction is estimated to affect approximately 30 million men in the United States and 159 million men worldwide. The Massachusetts Male Aging Studies published in 1994 found that over half of the men age 40-70 years in the United States has mild, moderate, or severe ED. We now know that ED is an important indicator of subsequent cardiovascular disease and strokes. We know that patients with ED have much higher levels of depression and have lower self-esteem.

There are many myths associated with sexual dysfunction. Three of the most prevalent myths are; that it is a psychological problem, that safe, simple, and effective treatments are not available for the majority of men, and that as a couple ages they become too old to enjoy sexual activity. Looking at the first myth, we know that the vast majority of ED is vasculogenic caused by diseases in the endothelial lining of the blood vessels within the penis. This endothelial disease is the same thing that causes the blockage of blood vessels in the heart (heart attacks) and the blockage of blood vessels in the brain (strokes). As to the second myth, we estimate that only 10% of the men who have ED in the United States have been treated even though we have very safe and effective oral preparations that will correct the problem in approximately 70% of patients. Regarding the third myth, the majority of couples never get too old to enjoy sexual function and urologists have treatments for virtually all patients at any age.

Physiology and Anatomy

The male penis is composed of two cylindrical structures that are attached to the male pelvis. Approximately 1/2 to 2/3 of the male penile length is outside the body and the remainder is inside the body. Blood supply to the penis comes from two small arteries arising in the male pelvis “pudendal arteries” which are lined with endothelial cells and smooth muscle. This artery courses through the pelvis and directly into the penis. In the flaccid state, this artery is only 0.5-0.8 mm in diameter. During the erect state, when the artery is relaxed by chemical reactions, the artery enlarges to 1-1.5 mm and the blood flow increases by a factor of 4.

Nerve impulses originate from the brain and travel down the spinal cord, run alongside the prostate, and then enter the penis. When stimulated, these nerves release a variety of chemicals that cause the endothelial cells and smooth muscles within the arterial walls and the penis to relax.

Within the penis are millions of sinusoidal spaces lined by endothelial cells and smooth muscle. When the male is not stimulated, the arteries leading to the penis are constricted, as are the sinusoidal cells within the penis. When the male becomes excited, the nerves fire and release chemicals that causes the smooth muscle to relax. As the arteries relax and open, the blood flow to the penis increases dramatically. As the sinusoidal cells relax, the blood is trapped within the penis and a rigid erection results. In the vast majority of men, diseases in the endothelial lining and smooth muscle is what leads to erectile dysfunction.

Evaluation and Treatment Options

DiagnosisThe introduction of Viagra™ has revolutionized the diagnosis and treatment of ED. Since it’s introduction, more than 7 million men worldwide have been successfully treated. The name recognition that Viagra™ has enjoyed in two short years puts it on level footing with products such as Coca-Cola in the world arena. In most cases, the evaluation and treatment of ED can be done in a single visit with your urologist. A detailed history and physical makes the diagnosis of ED and looks for reversible causes. Blood tests need to be done to confirm a normal level of male hormone (testosterone), assess your risk of other cardiovascular diseases (cholesterol, HDL, LDL) and to assure that you do not have renal disease, diabetes mellitus, or prostate cancer (metabolic screening profile and PSA). Assuming that you are on no form of nitrate medications (used for control of cardiovascular disease) and you do not have severe cardiovascular disease you may be given a prescription for Viagra™, Vardenafil (Levitra™) or a newer five phosphodiesterase inhibitor such as Tadalafil (Cialis™) which should be approved in early 2004. Only if those medications are ineffective will you require further testing and/or need to consider other treatment options.

Medical Therapy

Phosphodiesterase InhibitorsThe compelling safety and success of Sildenafil (Viagra™) have propelled this class of drugs to the forefront in treating ED. The phosphodiesterase (PDE) inhibitors are a class of drugs first tested to prevent cardiac spasm and heart attacks in men. While these drugs, which are specific for the PDE 5 isoenzyme, were only moderately successful for preventing cardiac spasm, their effect on improving male erections have changed the history of ED.

These drugs work by inhibiting a specific isoenzyme (PDE 5) in the penis through a series of complex chemical reactions, which eventually causes a better and more complete relaxation of the smooth muscle and thus a better erection. Side effects are typically caused by the presence of PDE 5 isoenzymes in blood vessels outside of the penis, resulting in headaches and/or flushing and cross over with other PDE 5 isoenzymes (PDE 6), which can cause a “blue haze” in the vision of a small number of individuals. Currently, three different drugs are approved in the United States: sildenafil (Viagra™), vardenafil (Levitra™), and tadalafil (Cialis™). All of the PDE 5 inhibitors block exactly the same enzyme and should theoretically have exactly the same effectiveness in treating ED. All three drugs will require sexual stimulation and will all be contraindicated with any form of nitrate use or severe cardiac disease. The differences will be in absorption, metabolism, and side effects of the drugs.

Sildenafil (Viagra™)

Sildenafil (Viagra™) is taken in a dose of 50-100 mg and its onset of action is 30 minutes to 1 hour after ingestion. It typically is effective for approximately 4-5 hours and its absorption is impaired if taken after a fatty meal. The primary side effects are headaches, flushing, and nasal congestion. In a small number of individuals a visual “blue haze” is noted. It has a proven record of safety and success in more than 10 million men. There is a precaution against using this drug within four hours of taking an alpha-blocker.

Vardenafil (Levitra™)

Vardenafil (Levitra™) appears to be a very similar molecule to Viagra™. Its onset of action is 30 minutes to 1 hour and its duration is approximately 4-5 hours. Its absorption after a fatty meal is also somewhat impaired. The main side effects include headaches, flushing, and nasal congestion. Its incidence of “blue haze” is less than that of Viagra™. This drug is contraindicated for use with any of the alpha-blockers.

Tadalafil (Cialis™)

Tadalafil (Cialis™) is taken in a dose of 10 or 20 mg. The onset of action is 30 minutes to 2 hours, but the duration in the majority of patients is up to 36 hours. Food intake has no effect on absorption and the incidence of “blue haze” is less than 0.1%. The primary side effects are headaches, flushing, nasal congestion, and occasional low back pain. It can be safely used with 0.4mg of tamulosin (Flomax™), but is contraindication with any of the other alpha-blockers.

Non-Medical Therapy

If the PDE 5 inhibitors are ineffective or are contraindicated, there are other very successful treatment options for men with ED. There are a variety of non-surgical vacuum devices available to patients. These types of devices will treat all forms of ED and are very safe. The downsides would be the time required to utilize them as well as the “muss and fuss” of jellies, rubber occlusive devices, and pumps.

MUSE™ is a small pellet, about the size of a grain of rice that is inserted into the male urethra. The pellet contains a chemical called Prostaglandin E-1, which is a smooth muscle relaxer. The medication is absorbed through the urethra into the penis, causing an erection within approximately 5-15 minutes. In those patients that are using nitrates, this is often a good form of therapy. Its side effects include mild urethral burning.

Penile injections involve a single chemical or multiple chemicals being injected into the penis with a very small insulin needle. These treatments work in approximately 70-80% of all patients, but they do require an injection for each use. Currently there is only one FDA approved injectable on the market, Alprostadil (Caverjet™). Other single agents such as Papaverin, Phentolamin, or mixtures of all three chemicals (Tri-Mix) have been effective in large numbers of patients, but they have to be used “off-label”. The advantages of these preparations are a very quick and rigid erection. The disadvantages are the injection itself, as well as penile scaring and a small risk of prolonged erections.

Another option, especially for patients with more severe vascular disease, is a surgically implanted penile prosthesis. There are currently 2 companies that manufacture these devices in a variety of types. The type most commonly placed in the United States is a fully inflatable model. These devices have the advantages of allowing the patient to look completely normal with or without and erection. When the patient desires an erection he pumps a small bulb located within the scrotum, which creates a completely normal appearing erection with normal sensation and a normal ability to ejaculate and climax. These devices are effective in approximately 95% of patients. They can be placed through a single 1-inch incision in about 45 minutes as an outpatient procedure. The patient does require pain pills for a week after implantation and cannot use the devices for a 6-week period. On average these devices last approximately 12-14 years. The downsides to these devices are the costs involved, the need for a surgical procedure, and a low risk of infection and mechanical complications.

Conclusion

Erectile dysfunction is a very common condition in the United States that dramatically affects the patient’s well being and quality of life. It is almost always caused by vasculogenic factors and is typically easy to treat. It is important to diagnosis this condition, as it is a predictor of cardiovascular disease. The evaluation and treatment can typically be done in a single office visit with minimal testing. Safe, effective oral preparations are available and appropriate in the majority of patients. In the event that oral preparations are contraindicated or are not effective, we have a variety of other therapeutic options that will allow virtually all patients to enjoy a healthy, fulfilling sexual relationship again.

 

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