ED: Erectile Dysfunction


Erectile dysfunction, commonly referred to as ED, is the inability to achieve and sustain an erection suitable for mutually satisfactory intercourse with his partner. This condition is not necessarily considered normal at any age and is different from other problems that interfere with sexual intercourse, such as lack of sexual desire and problems with ejaculation and orgasm.

Having erection trouble from time to time isn't necessarily a cause for concern. If erectile dysfunction is an ongoing issue however, it can cause stress, affect your self-confidence and contribute to relationship problems. Problems getting or keeping an erection also can be a sign of an underlying health condition that needs treatment and a risk factor for heart disease down the road.

Sometimes, treating an underlying condition is enough to reverse erectile dysfunction. In other cases, medications or other direct treatments might be needed.
Sexual health and function are important determinants of quality of life. Because this subject is discussed widely in the media, men and women of all ages are seeking guidance in an effort to improve their relationships and experience satisfying sex lives.

Sexual dysfunction is often associated with disorders such as diabetes, high blood pressure, heart disease, nervous system disorders, and depression. Erectile dysfunction may also be an unwanted side effect from medication. In some men, sexual dysfunction may be the symptom of such disorders that brings them to the doctor's office.

The successful treatment of impotence has been demonstrated to improve intimacy and satisfaction, improve sexual aspects of quality of life as well as overall quality of life, and relieve symptoms of depression.

Premature ejaculation is often confused with erectile dysfunction. Premature ejaculation is a condition in which the entire process of arousal, erection, ejaculation, and climax occur very rapidly, leaving the partner unsatisfied. Premature ejaculation may accompany an erection problem such as ED but is generally treated differently.

Failure to achieve an erection less than 20% of the time is not unusual and treatment is rarely needed. Failure to achieve an erection more than 50% of the time, however, generally indicates there is a problem requiring treatment.

Although this information focuses primarily on male ED, remember that the partner plays an integral role. If successful and effective management is to occur, any discussion of treatment should include the couple.


How do erections happen?


For a man to have an erection, a complex process takes place within the body.
    • Erection involves the central nervous system, peripheral nervous system, psychological and stress-related factors, local problems with the erection bodies or penis itself as well as hormonal and vascular (blood flow or circulation) factors. The penile portion of the process leading to erections represents only a single component of a very complex process.
    • Erections occur in response to touch, smell, and visual stimuli that trigger pathways in the brain. Information travels from the brain to the nerve centers at the base of the spine, where primary nerve fibers connect to the penis and regulate blood flow during erection and afterward.
    • Sexual stimulation causes the release of chemicals from the nerve endings in the penis that trigger a series of events that ultimately cause muscle relaxation in the erection bodies of the penis. The smooth muscle in the erection bodies controls the flow of blood into the penis. When the smooth muscle relaxes, the blood flow dramatically increases, and the erection bodies become full and rigid, resulting in an erection. Venous drainage channels are compressed and close off as the erection bodies enlarge.
    • Detumescence (when the penis is no longer in a state of erection) results when muscle-relaxing chemicals are no longer released. Ejaculation causes the smooth muscle tissue of the erection bodies in the penis to regain muscle tone, which allows the venous drainage channels to open and the blood drains from the penis.
What Causes Erectile Dysfunction?

Erectile dysfunction can be caused by any number of physical and psychological factors. In general, ED is divided into organic (having to do with a bodily organ or organ system) and psychogenic (mental) impotence, but most men with organic causes have a mental or psychological component as well.

Erection problems will usually produce a significant psychological and emotional reaction in most men. This is often described as a pattern of anxiety and stress that can further interfere with normal sexual function. This "performance anxiety" needs to be recognized and addressed.

  • Almost any disease can affect erectile function by altering the nervous, vascular, or hormonal systems. Various diseases may produce changes in the smooth muscle tissue of the penis or influence mood and behavior.
  • Vascular diseases account for nearly half of all cases of ED in men older than 50 years. Vascular disease includes atherosclerosis (fatty deposits on the walls of arteries, also called hardening of the arteries), a history of heart attacks, peripheral vascular disease (problems with blood circulation), and high blood pressure. Prolonged tobacco use (smoking) is considered an important risk factor for ED because it is associated with poor circulation and reduced blood flow in the penis.
  • Trauma to the pelvic blood vessels and nerves is another potential factor in the development of ED. Bicycle riding for long periods has been implicated, so some of the newer bicycle seats have been designed to soften pressure on the perineum.
  • Medications used to treat other medical disorders may cause ED.
  • Systemic diseases associated with ED
    • Diabetes
    • Scleroderma
    • Renal (kidney) failure
    • Liver cirrhosis
    • Hemochromatosis (too much iron in the blood)
    • Cancer and cancer treatment
  • Diseases of the nervous system associated with ED
    • Epilepsy
    • Stroke
    • Multiple sclerosis
    • Guillain-Barré syndrome
    • Alzheimer disease
    • Trauma
    • Parkinson disease
  • Respiratory disease associated with ED: Chronic obstructive pulmonary disease (COPD)
  • Endocrine conditions associated with ED
    • Hyperthyroidism
    • Hypothyroidism
    • Hypogonadism
  • Penile conditions associated with ED
    • Peyronie's disease
    • Priapism (painful, abnormally prolonged erections)
  • Mental conditions associated with ED
    • Depression
    • Performance anxiety
  • Nutritional states associated with ED
    • Malnutrition
    • Zinc deficiency
  • Blood diseases associated with ED
    • Sickle cell anemia
    • Leukemias
  • Surgical procedures associated with ED
    • Procedures on the brain and spinal cord
    • Retroperitoneal or pelvic lymph node dissection
    • Aortoiliac or aortofemoral bypass
    • Abdominal perineal resection
    • Proctocolectomy
    • Radical prostatectomy
    • Transurethral resection of the prostate
    • Cryosurgery of the prostate
    • Cystectomy
  • Common medications associated with ED
    • Antidepressants
    • Antipsychotics
    • Antihypertensives (for high blood pressure)
    • Antiulcer drugs such as cimetidine (Tagamet)
    • Hormonal medication such as Zoladex, Lupron, finasteride (Proscar), or dutasteride (Avodart)
    • Drugs that lower cholesterol
    • Alcohol abuse
    • Mind-altering agents such as marijuana and cocaine 

Diagnosis of ED:

The first step in the medical management of erectile dysfunction is taking a thorough sexual, medical, and psychosocial history. 

  • Your doctor will ask if you have difficulty obtaining an erection, if the erection is suitable for penetration, if the erection can be maintained until the partner has achieved orgasm, if ejaculation occurs, and if both partners have satisfaction.
  • You will be asked about current medications you are taking, about any surgery you may have had, and about other disorders (history of trauma, prior prostate surgery, or radiation therapy, for example).
  • The doctor will want to know all medications you have taken during the past year, including all vitamins and other dietary supplements.
  • Tell the doctor about your tobacco use, alcohol intake, and caffeine intake, as well as any illicit drug use.
  • Your doctor will be looking for indications of depression. You will be asked about libido (sexual desire), problems and tension in your sexual relationship, insomnia, lethargy, moodiness, nervousness, anxiety, and unusual stress from work or at home.
  • You will be asked about your relationship with your partner. Does your partner know you are seeking help for this problem? If so, does your partner approve? Is this a major issue between you? Is your partner willing to participate with you in the treatment process?
  • Your doctor will want your candid answers to questions like these:
    • How long has a problem existed? Did a specific event such as a major surgery or a divorce occur at the same time?
    • Do you have diminished sexual desire? If so, do you think it is just a reaction to poor performance?
    • How hard or rigid are your erections now? Are you ever able to obtain an erection suitable for penetration even momentarily? Is maintaining the erection a problem?
    • Can you achieve orgasm, climax, and ejaculation? If so, does it feel normal to you? Does the penis become somewhat rigid at climax?
    • Do you still have morning erections?
    • Is penile curvature (Peyronie's disease) a problem?
    • What would be your preferred frequency of intercourse, assuming the erections were working normally? How would your partner answer this same question? What was your frequency before the erections became a problem?
    • Have you already tried any treatments for ED yet? If so, what were they and how did they work for you? Were there any problems or side effects to their use?
    • Are you interested in trying a particular treatment first? Are you against trying a particular type of therapy? If so, what caused you to make this judgment?
    • To what degree do you wish to proceed in determining the cause of your ED? How important is this information to you?



A physical examination is necessary. The doctor will pay particular attention to the genitals and nervous, vascular, and urinary systems. Your blood pressure will be checked because several studies have demonstrated a connection between high blood pressure and erectile dysfunction. The physical examination will confirm information you gave the doctor in your medical history and may help reveal unsuspected disorders such as diabetes, vascular disease, penile plaques (scar tissue or firm lumps under the skin of the penis), testicular problems, low testosterone production, injury, or disease to the nerves of the penis and various prostate disorders.

Testing for ED:


Laboratory testing: 
    • If laboratory tests are performed, they would normally start with an evaluation of your hormone status (testosterone or male hormone), particularly if one of your symptoms is low sexual desire (low libido). Blood tests for testosterone should ideally be taken early in the morning because that's when levels are usually at their highest. Other blood tests, such a luteinizing hormone and prolactin, can help determine if there is a problem with the pituitary gland.
    • Your blood may be checked for glucose, cholesterol, thyroid function, triglycerides, and prostate-specific antigen (PSA).
    • A urinalysis looking for blood cells, protein, and glucose (sugar) may also be done.

  • Imaging: An ultrasound may be performed. This test may be done on the lower abdomen, pelvis, and testicles, or restricted to just the penis.
    • A duplex ultrasound is a diagnostic technique that uses painless, high frequency sound waves to visualize structures beneath the skin's surface. The principle is similar to the sonar used on submarines. Sound waves are reflected back when they contact relatively dense structures such as fibrous tissue or blood vessel walls. These reflected sound waves can be converted into pictures of the internal structures being studied.
    • This procedure is usually performed before and after injection of a smooth muscle relaxing medication into the penis, which normally should significantly increase the diameter of the penile arteries. The procedure itself is painless. Duplex ultrasonography is most useful in evaluating possible penile arterial disorders, but further studies of the venous drainage system as well as arterial x-rays are usually recommended if vascular reconstructive surgery is anticipated.

  • Further testing: Following completion of this phase, the doctor should be able to determine the general type of dysfunction and the need for additional testing such as penile or pelvic blood flow studies, penile biothesiometry (nerve testing), or additional blood tests. 
    • One of the most common tests used to evaluate penile function is the direct injection of PGE1 into the penis. (PGE1 is a medication that increases blood flow into the penis and normally produces erections.) If the penile structure is normal or at least adequate, an erection should develop within several minutes. You and your doctor can judge the quality of the erection. If successful, this test also establishes penile injections as one possible therapy.
    • Formal neurological testing is not needed for most men. But anyone with a history of nervous system problems such as loss of sensation in the arms or legs and those with a history of diabetes may be asked to undergo testing.
Treatment for Erectile Dysfunction:

Many treatment options exist. Options include counseling, medications, external vacuum devices, hormonal therapy, penile injections or intraurethral suppositories. In selected cases of ED, combination therapy using several of these methods together can be used. If none of these therapies is satisfactory, penile prosthesis implants can be considered.


Medical Management of ED:


Viagra: Sildenafil citrate is a prescription medication for the treatment of erectile dysfunction. It was the first oral medicine initially introduced in March 1998. 
    • Viagra works by blocking an enzyme found mainly in the penis that breaks down a chemical produced during stimulation that normally produces erections. Viagra allows this chemical of arousal to survive longer and improves erection function. That is also why sexual stimulation is necessary for Viagra to work.
    • In general, Viagra works successfully in about 65-70% of all impotent men. The greater the degree of damage to the normal erection mechanism, the lower the overall success rate. Men with diabetes and those with spinal cord injury reported between 50-60% responding successfully to treatment with Viagra. The worst response rate was in men who became impotent after radical prostate cancer surgery. But even in this hard-to-treat group, 43% reported improved erections particularly if they had the "nerve-sparing" type of prostate surgery.  
Viagra works best if taken about one hour before sexual activity. Only one tablet should be taken per day. It is most effective if  taken on an empty stomach or at least a low fat meal. Increasing the dosage of Viagra beyond the recommended amounts will not improve the response and will only result in greater side effects.

  • The most common side effect of Viagra use is headache, affecting about 16% of users. A drop in blood pressure, transient dizziness, and facial flushing are reported in 10%. Indigestion occurs in 7%, and nasal congestion in 4%.
    • Between 3% and 11% of users report some visual problems while on Viagra. This visual disturbance is described as either blurred vision, increased light sensitivity, persistence of a bluish tinge or temporary loss of the ability to distinguish between blue and green.
    • None of these side effects is severe and most are described as mild. Very few users stop taking the medication because of side effects.
    • Viagra is absolutely not to be taken by men with heart conditions who are taking nitrates such as nitroglycerine or isosorbide (Isordil, Ismo, Imdur). Those with serious heart disease, exertional angina (chest pain), and those taking multiple drugs for high blood pressure are advised to seek the advice of a heart specialist before beginning therapy with sildenafil.
    • No nitrate-based drugs should be given to men with suspected heart attacks if they have taken Viagra within 24 hours. Combining Viagra with nitrate-based medications can cause a severe and dramatic drop in blood pressure with potentially very dangerous consequences. This is also why you should absolutely never share your Viagra prescription with anyone else. If they happen to be taking one of the drugs that interacts dangerously with Viagra, the results could be very serious. If there is any question about possible drug interactions, always check with your doctor or pharmacist.
    • Several medications can interfere with the chemical processing of Viagra by the liver. These can include ketoconazole (an antifungal medication known by the brand name Nizoral), erythromycin (an antibiotic), and cimetidine (also known as Tagamet, for reducing stomach acid). A lower dose of Viagra should be used if you are taking any of these medications.
    • Sildenafil is available in 3 doses: 25 mg, 50 mg, and 100 mg. The starting dose depends on the clinical situation. A man in his 50s with mild sexual dysfunction that is probably related to psychological factors can start on the 25 mg dose. Men with moderate-to-severe ED can begin at the 50 mg dose, and, after testing the effect of the drug on at least 3 occasions, the dose can be modified. Men with severe ED may need to quickly move up to the 100 mg dose. These men are less likely to achieve a satisfactory response, but they should make at least 3-4 attempts with the drug before considering another form of therapy.
  • Sildenafil should be taken on an empty stomach about 45-60 minutes prior to sexual intercourse. Stimulation is necessary to produce an erection. An increased ability to achieve good erections can last up to 24 hours but usually only about 4 hours. The drug should not be taken daily


  • Several drugs very similar to Viagra are available. These drugs, called vardenafil (Levitra), tadalafil (Cialis), and avanafil (Stendra). have essentially the same activity and general precautions as Viagra. Cialis has a longer duration of action to develop an erection (up to 24-36 hours) compared with Viagra and Levitra (up to 4 hours) and can be taken daily in a lower dosage if desired.

Hormonal (testosterone) therapy: is only considered a medical treatment for ED if sex drive or libido is a direct cause for decreased sexual performance. Learn more about Low T and Testosterone replacement.
Vacuum devices: 

Specially designed vacuum devices to produce erections have been used successfully for many years. They are safe and relatively inexpensive. They work by using a manually generated vacuum to draw blood into the penis to create the erection. When used successfully, their other significant benefit is a high degree of reliability compared to drug treatments, which tend to be less predictable. The typical vacuum device consists of a plastic cylinder that is placed over the penis, tension rings of various sizes, and a small hand pump. Air is pumped out, causing a partial vacuum, which creates the erection. Once an erection is obtained, a tension ring, which acts like a tourniquet to keep the blood in the penis and maintain an erection, is placed at the base of the penis. This technique is effective in 60-90% of men. It is not recommended to leave the tension ring in place longer than 30 minutes.
Injection Therapy:

Intramuscular injection of testosterone every 2-4 weeks. Dosing is specific to the patient and his response to treatment.