Dr Nguyen Hoang Duc


ED is the inability of a man to achieve or maintain an erection sufficient for his sexual needs or the needs of his partner. Most men experience this at some point in their lives, usually by age 40, and are not psychologically affected by it.

Some men, however, experience chronic, complete erectile dysfunction (impotence), and others, partial or brief erections. Frequent erectile dysfunction can cause emotional and relationship problems, and often leads to diminished self-esteem. Erectile dysfunction has many causes, most of which are treatable, and is not an inevitable consequence of aging.

There is a significant negative impact on the quality of life for the patient and his partners. It used to be thought that almost all cases of impotency were psychological in origin. This is not the case today. However, many patients do have some psychological overlay to the problem. Impotency is intensely intertwined with manliness and loss of erections often provides great anxiety in the patient. This anxiety to perform is often the cause of continued problems even after correction of the initiating cause of the impotency. We call this anxiety performance failure or fear of failure.
The anxiety associated with whether there will be a failed erection induces such failure. This is often unconscious in nature and the patient is unaware of the degree that the mind is playing in the continued failure. One cannot will an erection up, but one can prevent such from happening. As our anxiety level rises, we liberate epinephrine from our sympathetic nervous system. This compound in very minute amounts causes the artery going into the penis to constrict, thus reducing the blood flow in and resulting in a lack of or a loss of the erection.
As a society, we are very much performance orientated. That is, we are concerned not about the quality of the lovemaking, nor whether our partner or we are satisfied, but whether it works. It is because of this that the couple often needs to have a better understanding of what it is that each expects from the other, followed by a change in how we make love, what our attitudes are, and how we interact with our partner in order to help correct the problem.
Incidence of ED
According to the National Institutes of Health, an estimated 30 million men in the United States experience chronic erectile dysfunction and incidence of the disorder increases with age. Chronic ED affects about 4% of men in their 50s, nearly 17% of men in their 60s, and about 47% of men over the age of 75. Transient ED and inadequate erection affect as many as 50% of men between the ages of 40 and 70.
Diseases (e.g.,diabetes, kidney disease,alcoholism,atherosclerosis) account for as many as 70% of chronic ED cases and psychological factors e.g.,stress,anxiety,depression) may account for 10–20% of cases. Between 35 and 50% of men with diabetes experience ED
Causes of ED
The causes of impotency are quite varied. It may be due to an infection or congestion of the prostate, side effect of medication or drugs, cigarette smoking, blockage of the blood vessels to the penis, damage to the nerves of the penis, lack of hormones, or associated with some diseases such as Peyronie's disease, diabetes, trauma to the pelvis or post-operative from such surgeries as resection of the prostate or radical surgery on the bladder, prostate, or colon

Vascular Disease
Arteriosclerosis, the hardening and narrowing of the arteries, causes a reduction in blood flow throughout the body and can lead to impotence. It is associated with age and accounts for 50% to 60% of impotence in men over 60.
Risk factors for arteriosclerosis include:
Diabetes mellitus
High blood pressure
High cholesterol
Smoking, which can lead to any of the above risk factors, is perhaps the most significant risk factor for impotence related to arteriosclerosis.
Diabetes Mellitus
Chronic high levels of blood sugar associated with diabetes mellitus often damage small blood vessels and nerves throughout the body, which can impair nerve impulses and blood flow necessary for erection. About 60% of men with diabetes experience impotence.
Over 200 commonly prescribed drugs are known to cause or contribute to impotence, including drugs forhigh blood pressure, heart medications, antidepressants, tranquilizers, and sedatives. A number of over-the-counter medications also can lead to impotence. Long-term use of alcohol and illicit drugs may affect the vascular and nervous systems and are associated with erectile dysfunction.
Hormone Imbalances
Hormone disorders account for fewer than 5% of cases of impotence. Testosterone deficiency, which occurs rarely, can result in a loss of libido (sexual desire) and loss of erection. Among other conditions, an excess of the hormone prolactin, caused by pituitary gland tumor, reduces levels of testosterone. Hormone imbalances can also result from kidney or liver disease.
Neurologic Conditions
Spinal cord and brain injuries (e.g., paraplegia, stroke) can cause impotence when they interrupt the transfer of nerve impulses from the brain to the penis. Other nerve disorders, such as multiple sclerosis (MS), Parkinson's disease, and Alzheimer's disease, may also result in impotence.
Pelvic Trauma, Surgery, Radiation Therapy
Trauma to the pelvic region or spinal cord can damage veins and nerves needed for erection. Surgery of the colon, prostate, bladde, or rectum may damage the nerves and blood vessels involved in erection. Prostate and bladder cancer surgery often require removing tissue and nerves surrounding a tumor, which increases the risk for impotence.
New nerve-sparing techniques aimed at lowering the incidence of impotence to 40 to 60 percent are now being developed and used in these surgeries. Temporary impotence is also associated with these procedures, even those in which nerve-sparing techniques were used. It can take as long as 6 to 18 months for full erections to return.
Radical cystectomy (for bladder cancer) and prostatectomy (for prostate cancer) require cutting or removing nerves that control penile blood flow. These nerves do not control sensation in the penis and are not responsible for orgasms; only erection is affected by these procedures.
Radiation therapy for prostate or bladder cancer also can permanently damage these nerves.
Peyronie's Disease
Peyronie's disease is a rare inflammatory condition that causes scarring of erectile tissue. Scarring produces curvature of the penis that can interfere with sexual function and cause painful erections.
Venous Leak
If the veins in the penis cannot prevent blood from leaving the penis during erection, erection cannot be maintained. Venous leak can be a result of injury, disease or damage to the veins in the penis.
Psychological Conditions
Depression, guilt, worry, stress, and anxiety all contribute to loss of libido and erectile dysfunction. If a man experiences loss of erection, he may worry that it will happen again. This can produce anxiety associated with performance and may lead to chronic problems during sex. If the cycle is inescapable, it can result in impotence. Psychological factors in impotence are often secondary to physical causes, and they magnify their significance.
Diagnosis and evaluation
Initially, the patient is evaluated with a detailed medical and sexual history to determine the type of problem, and for how long the problem has existed. The problem is manifested in many ways such as a decrease in one's sexual desire, difficulty in getting a satisfactory erection, difficulty in maintaining an erection, decrease in the quality of the erection, difficulty in ejaculating, pain or blood in the ejaculate, or premature ejaculation.

In general, there is a logical and step-wise evaluation to determine the cause of the problem, which in addition to the history usually consists of a physical examination, blood testing and at times, blood pressure measurements of the penis or x-rays of the corpora of the penis.
The physical exam not only involves the genitourinary system, but also looks for signs of other medical problems that can cause erectile dysfunction, especially arteriosclerosis, Diabetes (sugar) and high blood pressure. Lab tests usually include a general battery of blood tests and urine analysis to include a general electrolyte panel, renal function, glucose, liver function, urine dipstick and testosterone level.
Treatment options
Treatment of erectile dysfunction is largely dependent on what the cause is. If there is a significant psychological component to the current erectile function and the NPT studies prove that the patient has normal nocturnal erections (your unconscious erections throughout the night, which all males with intact erectile function have), you will be referred for sex counseling or therapy. If there is an organic component the usual course of therapy is from the most conservative treatment to finally surgery. The order of therapies used by our physicians is
If testosterone (total and free component) are low, we will start with hormone replacement.

  • Testosterone injections
  • Testosterone patches

Oral Medication

  • Viagra has no effect in the absence of sexual stimulation; it merely augments blood flow to the penis. You must provide sexual stimulation (foreplay, masturbation and/or sexual videos) to your penis in order for Viagra to help with increasing the effectiveness of your erections.
  • You must take Viagra ½ - 1 hour before you plan to have intercourse. The duration of effect for the medication is approximately 4 hours.
  • Take the Viagra on an empty stomach. A large fatty meal will delay the absorption and effectiveness of the Viagra.
  • The most common side effects of Viagra are:
    • Headache - 15%
    • Flushing (face and upper torso) - 10%
    • Upset stomach/dyspepsia - 6%
    • Nasal congestion - 4%
    • Visual changes (blue/green impairment)/light sensitivity - 3% 
      (These side effects are only transient and should go away 3-4 hours after taking the Viagra. If they persist, call your physician).
  • There has been only a 2.3% drop out rate over long term use related to the side effects noted above. Higher doses have higher incidence of side effects.
  • There are no reported cases of priapism (extended erections longer than 4 hours).
  • Taking more than the prescribed dose will not enhance the action of the drug; it may only increase its side effects.
  • Viagra should only be taken once in a 24-hour period/day.
  • Drink no more than two drinks of alcohol in the same 24-hour period that you take Viagra.
  • Do not use with other medications for erections unless instructed by your physician/urologist. Viagra can be used with MUSE or penile injections if tested first at your urologists office

Minimally invasive therapies
  • Penile Injections: penile injection of Papaverine/Regitine and Prostaglandin's, individually or in various combinations
  • Vacuum Tumescence Devices
Surgical Services
Penile implants.

Home Introduction For Patients For Doctors Download Contact us