What is Male Erectile Dysfunction or Impotence?

This problem affects at least 30 percent of all adult males and 50 percent of all males over 40 years of age. Some 85 percent of the causes for MED are physical and are organic and due to an actual physical problem, disease entity, or complication of another illness. In general, 40 percent of all 40-year-olds, 50 percent of all 50-year-olds, and 60percent of all 60-year-olds have some form of MED although in general only 15 percent are of the severe form, that is to say inability to totally obtain any erections whatsoever.

With the advent of an effective oral and safe medication Viagra (Sildenafil) the entire evaluation and treatments for male erectile dysfunction have become revolutionized. Other forms of therapy including self injection programs with vasoactive drugs, intraurethral placement of vasoactive drugs, external vacuum compression device, and implantation of inflatable penile prostheses are still available and have a place in the armamentarium of the urologist who deals in the problems of sexual dysfunction in men.

In general, with the advent of Viagra in March of 1998 the numbers of patients seen by physicians have increased two-fold, and in general up to 75 percent of the patients will respond to Viagra. The remainder will need other treatment modalities, some of which include combinations with Viagra. Any physician can prescribe Viagra; however the specialists who know the most about Viagra are urologists who specialize in the field of male sexual dysfunction. In those cases in which Viagra does not work, where the results are suboptimal, or in situations in which the cause for the impotence is not obvious, a patient should be seen by a specialist.

Further information can be obtained in other sections of this web site:

1. Diagnosis and evaluation.
2. Special testing.
3. Treatment modalities.
   1. oral medications
   2. intraurethral pellets
   3. injectable vasoactive drugs
   4. external vacuum compression devices
   5. implantable penile prosthetic devices
   6. future treatment modalities

Diagnosis and Evaluation:

Of the thirty million American men with chronic impotence not all need significant and expensive diagnostic evaluations. Patients with an obvious cause for their sexual dysfunction or patients over 60 years of age probably need a minimal amount of diagnostic testing. Most of the tests necessary are blood tests frequently done by their primary care or internal medicine physicians. If there is a sexual desire problem a total testosterone and a prolactin blood test should definitely be performed in addition to the routine blood count and chemical profiles most patients normally have. For this group of patients a trial of Viagra would be best, and if response is good without side effects continuation of the drug should be done.

On the other hand, in that group of impotent men who are under 60 years of age and the diagnosis is not obvious, diagnostic testing should be performed to determine the etiology of their sexual dysfunction even if Viagra in the end is an effective form of therapy. Remember, the sexual dysfunction of impotence is a symptom of another problem.

Many times the other problem can be resolved which will resolve the sexual dysfunction. In addition, frequently the other problem has medical sequelae that are more dangerous than the impotence. For example, one-third of the patients who have undiagnosed cardiovascular disease and who present with impotence as the first symptom of their cardiovascular problem will have some cardiovascular complication such as a heart attack or stroke within three years of diagnosing or treatment their sexual dysfunction.

This group of patients requiring special diagnostic studies should certainly be seen by their urologic specialist who will not only do the routine bloods, CBC and chemistry profile, and the hormone studies, total testosterone, prolactin, and possibly free testosterone with LH and FSH levels, but will seriously consider doing nocturnal penile sleep studies to determine whether this is a physical organic problem or a psychogenic problem. The reason for doing these sophisticated studies is not just to determine the cause, but also to give a prognosis as to how long treatment may be necessary, and lastly to objectively measure the severity of the problem and assist in determining how much medicine or treatment will be necessary and what doses should be started with.

In rare situations probably representing less than 10 percent of patients who are young, the diagnosis is organic on the basis of sleep studies (Rigiscan testing), and where the blood studies are normal including hormone studies; the urologist specialist may consider more aggressive vascular testing procedures including Doppler flow studies of the penis, angiography, and x-ray pictures of the penis in the erect state using contrast material (cavernosometry) along with penile pressure studies (cavernosometrics).

Special Diagnostic Tests:

Obviously basic blood studies including blood count, CBC, chemical profile, and hormone tests including the male hormones testosterone total and free, prolactin, and the pituitary luteinizing hormones (LH) and follicle stimulating hormone (FSH) are frequently drawn on a routine basis. General illness can be determined from the red and white blood counts. Kidney and liver function which can affect sexual function are determined by certain chemical evaluations such as the BUN, creatinine, and various enzyme studies including the bilirubin. Diabetes can be ruled out or questioned based upon the blood sugar level, and obviously patients who have elevated cholesterol and triglycerides run a greater risk of high blood pressure and hardening of the arteries.

The male hormone testosterone should absolutely be performed in patients who have poor sexual desire since most impotent men have normal desire with normal hormone levels. Desire problems are frequently found only in patients with elevated prolactins which should also be obtained, low testosterones, or psychogenic causes for their erectile dysfunction.

Nocturnal Penile Tumescence (Rigiscan Sleep Studies)

Sleep studies, in general, should only be performed in younger males, i.e. less than sixty years of age in which the etiology of the impotence is not obvious and all patients, no matter what their age, if they wish to differentiate psychological from organic causes for the sexual dysfunction and possibly the specific etiology of their organic disease. Sleep studies, in general, are based upon the principle that all men from birth to death, have erections every ninety minutes, three to five times at night lasting fifteen to thirty minutes of a certain intensity and rigidity.

Patients with a psychological cause for their impotence will have a perfectly normal sleep biorhythm, whereas patients who have a physical cause (organic) will have some abnormality of the frequency, intensity or duration of their sleep erections. Other nonquantitative ways of measuring sleep erections would include the stamp test in which a roll of stamps are placed around mid-shaft of the penis with the sticky side out for two to three nights to see if the stamps break, i.e., indicating at least one good erection to break the stamps.

Or, using a more sophisticated stamp test called the Snap Gauge manufactured by Dianon Corporation which not only tells you that there is one good erection at night, but it also determines the strength of the erection, i.e., weak, moderate, or strong. In general, Rigiscan sleep studies are the best way of determining what the nocturnal erection sleep cycle is like. Men can have one good erection at night, but this is, in fact, not normal, since most men have three to five erections at night. Snap Gauge and stamp tests will only demonstrate one erection and cannot quantitatively demonstrate the other erections at night.

Cavernosometrics and Cavernosometry

In very unusual and rare situations, in order to demonstrate a venous leak problem, doctors may do cavernosometry and cavernosography. In cavernosometry saline is infused into the corpora cavernosa after inducing an erection, usually with Prostaglandin intracavernosal pharmacotherapy and determining how many ccs of water it takes to maintain the erection. If dye is injected into the penis with a tourniquet around the base of the penis one can also determine the venous outflow of the penis, see if the leakage is focal and surgically correctable, or as in most situations a diffuse leak which is not correctable.

Most cases of venous leak problems are really arterial insufficiency problems and the handling of venous leak is through the increase of blood flow into the penis by other therapies including Viagra, intraurethral Prostaglandin (Muse), and/or intracavernosal injections of pharmacologically active drugs such as Prostaglandin E-1 (caverject).

Pudendal Angiography

Again, in rare and unusual circumstances in which a relatively young male, under 55 years of age, who has a history of pelvic trauma from an automobile accident and/or motorcycle accident in which the pelvis was fractured, would pudendal angiography be considered. Before doing the angiography a Doppler flow study or digital flow studies of the penis would be done to see if there was abnormal flow to the various arteries of the penis. In those circumstances in which the Doppler flow or digital flow was abnormally low, and at which there was an appropriate history of a pelvic fracture in a relatively young diabetic male, pudendal angiography could be considered, especially if it was felt that arterial reconstructive surgery would be helpful in this patient. In general, arterial reconstructive surgery for impotence is unsuccessful since most patients are elderly, already have small vessel vascular disease, or are diabetic. Doppler flow studies and angiography would not be done in most of these circumstances.

Treatment Modalities

A. Oral Medications

Oral medications at this time include Viagra (Sildenafil) a potent type 5 phosphodiesterase inhibitor, yohimbine, trazodone (Desyrel), and methylated testosterone. In general, Viagra is the most potent and best way of handling male erectile dysfunction. It was introduced on March 27, 1998 and is effective in approximately 75-80 percent of all men with erectile dysfunction, 40 percent of all men with radical prostatectomies, and most men with psychogenic impotence. Viagra should probably be tried by all men who have erectile dysfunction no matter what degree of impotence they have. The only contraindications include: taking of organic nitrates and nitroglycerin, Sildenafil hypersensitivity, severe cardiac disease in which sexual function if prohibited, and the rare eye disease retinitis pigmentosa. The drug is taken one to four hours prior to sexual activity and needs sexual stimulation to be effective. The side effects include: mild headaches, facial flushing, stomach upset and unusual ocular disturbances including a bright vision and a blue-green halo around the vision.

When these symptoms occur they are usually of short duration, lasting less than 15 to 30 minutes and of mild degree and always self limiting. In the future there will be newer, more potent and more specific Viagra-like drugs. All these drugs work by inhibiting the inhibitor cyclic GMP, therefore causing an increased production of nitric oxide by the lining of the blood vessels of the penis. The nitric oxide acts as a potent poison to the muscles of the blood vessels, dilating the blood vessels, increasing blood flow to the penis and causing penile engorgement.

Yohimbine such as in the form of Yocon 5.4 mg has been used in the past and is effective in approximately 25-35 percent of patients with erectile dysfunction. There is question whether it has a true pharmacologic effect, and whether or not its major effect is placebo. Its major side effects are: hypertension, cardiac arrhythmia, and anxiety production. With the introduction of Viagra, the question arises whether yohimbine should or should not be utilized by urologists who specialize in this field.

Trazodone or Desyrel is an antidepressant whose side effects include an erection that will not go away, i.e. priapism. In depressed impotent men this drug may have a place although with the advent of Viagra its use is limited.

Oral testosterones in the form of methylated testosterone should probably never be used because of its major and serious side effect cholestatic jaundice and hepatic toxicity. If patients are found to be testosterone deficient then utilization of injectable Depo-testosterones 200 mg every two to three weeks or Androderm testosterone patches 5 mg nightly should be utilized. Testosterone replacement will improve sexual desire in men who are testosterone deficient, but will improve their sexual function only 50 percent of the time since there are other factors involved in many of these men including vascular disease, diabetes, etc.

B. Intraurethral Drugs

Intraurethral pellets (Muse) was the second medication approved by the FDA Food and Drug Administration for the treatment of male erectile dysfunction. It is effective in approximately 40 percent of males with erectile dysfunction. It is best used in those patients with mild to moderate symptoms. Its major side effect is irritation of the urethra and penile discomfort which occurs in only 3 percent of patients.

When used in conjunction with Viagra oral medication the two drugs are synergistic in their effect and make for an excellent combination therapy in those patients in which the Viagra is suboptimal and/or Muse suboptimal. There have been no studies on the combination of Viagra and Muse and therefore the Viagra package insert states that it is not indicated together. On the other hand, among urologists who treat impotence, the combination is excellent and should be tried under physician management. Muse therapy comes in the dosages of 125, 250, 500, and 1,000 mcg.

A small toothpick-like applicator holds the 3 mm pellet which is placed into the urethra quite easily and painlessly. Massage of the penis within five to ten minutes causes its erectile effect. 90 percent of the drug is hydrolyzed in the urethra, and only approximately 10 percent get absorbed into the spongy rods of the penis as prostaglandin.

C. Injectable Vasoactive Drugs

The vasoactive drugs that are available for injection therapy include Prostaglandin E-1 (Caverject, Edex), papaverine and Regitine, Trimix (papaverine, Regitine plus Prostaglandin E1), and vasoactive intestinal polypeptides (VIP). See planetrx.com for more information. Caverject, manufactured by the UpJohn Company, was the first drug to be FDA approved for the treatment of impotence.

The drug is injected directly into the two spongy rods that make up the penis at its base where sensation is minimal using a small-gauged needle and injecting approximately 5 to 20 micrograms of prostaglandin per dose. The drug is only injected prior to sexual activity, taking about five to ten minutes to be active, and lasting anywhere from one to two hours. It is extremely effective and works in more than 95 percent of patients.

Contrary to what most people think, the base of the penis has minimal pain fibers and injection into the base of the penis at the two or ten o'clock position causes minimal to no discomfort. For those men who are unable to place a needle directly into the body an autoinjector is available. The major complications of intracavernosal Prostaglandin includes penile discomfort in 3 percent of cases, most rare priapism, and even rarer using good technique would be injury to the urethra.

Prior to the widespread use of Prostaglandin, combinations of papaverine and Regitine were utilized in the United States. In circumstances in which there is penile pain with injectable Prostaglandin, papaverine and Regitine are still utilized. On some occasions papaverine and Regitine works better than Prostaglandin and vice versa. The major problems with papaverine and Regitine are its effect on the liver it cannot be used in patients with chronic liver disease, and an erection that will not disappear, i.e., priapism.

On rare occasions when Prostaglandin alone or papaverine and Regitine are not effective, the three are combined into what is called Trimix and may be injected in an effective manner.

Vasoactive intestinal polypeptides (VIP) have been researched in the Scandinavian countries for injection in the treatment of impotence. This drug has not been approved in the United States, it is expensive and not easily available, and it also causes penile discomfort.

D. External Vacuum Compression Devices

External vacuum compression devices are effective in approximately 75 percent of patients. However, the learning curve is significant, it takes a great deal of perseverance to learn and utilize, but when mastered can be used quickly and effectively. It involves placing a plastic cylinder over the shaft of the penis, pressing against the base of the pelvis and pumping some type of a vacuum device which produces a vacuum in the cylinder sucking blood into the penis and allowing an erection to form.

As the vacuum is released and the cylinder is removed, a compressor band is slipped over the base of the penis holding the blood within the penis. Many people find this cosmetically unpleasant and therefore would not utilize. There have been no significant serious problems related to a vacuum compression device if used properly, and if the constriction band is not allowed to remain in place more than thirty minutes.

The device is contraindicated in those patients who have sickle cell disease or significant anticoagulant therapy, or have some type of blood dyscrasia and bleeding problem. There are approximately 15 to 20 manufacturers of these devices with costs ranging between $89 and $400. Most of the vacuum-producing components are mechanical; however, there are battery operated devices as well.

E. Implantable Penile Prosthetic Devices

Penile prostheses are implanted in those patients in whom all other therapies are ineffective or suboptimal or in which the patient is not willing to utilize other treatment modalities. In general, penile prostheses are the final way to resolve an impotence situation. It works, and patient satisfaction is greater than 99 percent. Partner satisfaction is approximately 98 percent. The negative press given to penile prostheses is unwarranted and for appropriate patients is an excellent way of resolving their erectile dysfunction.

The different penile prostheses include semi-rigid malleable devices, self-contained inflatable devices, and multi component inflatable devices. In most cases the multi-component inflatable device should be utilized since it has the best quality erectile function with the best cosmetic flaccid situation. The self-contained prostheses should probably be used in those males who cannot have a reservoir within the retroperitoneum due to extensive previous surgery, but these devices do not have the flaccid and tumescent properties of the multi-component variety. Semi-rigid devices; however, can be utilized in those men who are incapable of utilizing their hands and do not have partners to manipulate their inflatable devices.

The inflatable penile prostheses are manufactured by two companies; American medical Systems in Minnetonka, Minnesota and Mentor Corporation in Santa Barbara, California. The 10 year success rate is in the range of 95-97 percent. Major complications include infection and device malfunction. Infection occurs in less than 0.5 percent of the nondiabetic population, and 1.5 percent of the diabetic population. Obviously, surgery is necessary for all penile implants taking anywhere from 40 minutes to an hour and a half to actually do the implantation under general or spinal anesthesia as a morning admission with a 23 hour stay or in and out. Revisions are almost always an in and out procedure.

Patients are placed on prophylactic antibiotics just prior to, at the time of, and after their surgery. Significant discomfort lasts less than two weeks and most of the devices are functional within four to six weeks, at which time pain and swelling has disappeared.

F. Future Treatment Modalities

Obviously, an oral drug that will effectively and safely treat erectile dysfunction is the most desired. Viagra appears to meet this description, but does have some minor side effects and cannot be utilized with nitrates. A long-acting, slow-release Viagra drug, as well as a rapid release tablet is being studied at this time. In addition, other oral medications that don't work through phosphodiesterase or cyclic GMP system are being tried as well. Creams including nitroglycerin and prostaglandin are also in investigational trials. The use of genetic therapy in which nitric oxide-producing enzymes are genetically infected through virus transfer have been experimented in animal studies.

by
Myron I. Murdock, M.D., FACS
Medical Director, hisandhershealth.com