Erectile dysfunction (ED) is the inability to attain or sustain an erection satisfactory for sexual intercourse.
(See also Overview of Sexual Function and Dysfunction in Men.)
Every man occasionally has a problem achieving an erection, and such occurrences are considered normal. Erectile dysfunction (ED) occurs when a man
Never achieves an erection
Repeatedly achieves erection briefly but not long enough for intercourse
Achieves effective erection inconsistently
ED is called primary if the man has never been able to attain or sustain an erection.
ED is called secondary if it is acquired later in life by a man who was previously able to attain erections.
Secondary ED is much more common than primary ED.
In the United States, ED is very common and increases in prevalence with age, with the majority of men over the age of 50 being affected. However, ED can be successfully treated at any age.
Causes of Erectile Dysfunction
To achieve an erection, the penis needs an adequate amount of blood flowing in, a slowing of blood flowing out, proper function of nerves leading to and from the penis, adequate amounts of the male sex hormone testosterone, and sufficient sex drive (libido). A disorder of any of these systems may lead to erectile dysfunction (ED).
Most cases of ED are caused by abnormalities of the blood vessels or nerves of the penis. Other possible causes include hormonal disorders, structural disorders of the penis, use of certain medications, and psychological problems (see table Common Causes and Features of Erectile Dysfunction). The most common specific causes are
Hardening of the arteries (atherosclerosis) that affects the arteries to the penis
Complications of prostate surgery (such as robotic prostatectomy for prostate cancer)
Certain medications, such as those used to treat high blood pressure or an enlarged prostate and those that act on the central nervous system, such as medications used to treat depression
Did You Know...
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Often several factors contribute to ED. For example, a man with a slight decrease in erectile function caused by diabetes or peripheral vascular disease can develop severe ED after starting a new medication or if stress increases.
Blood vessel disorders
Atherosclerosis may partially block blood flow to the legs (peripheral vascular disease). Usually, arteries to the penis are also blocked, decreasing the amount of blood flow to the penis and causing ED. Diabetes, high cholesterol levels, high blood pressure, and smoking contribute to atherosclerosis and therefore to ED.
Sometimes blood leaks out of the veins in the penis too quickly, decreasing blood pressure in the penis and thus interfering with achieving or maintaining an erection (called veno-occlusive dysfunction or venous leak).
Nerve disorders
If the nerves sending messages to the penis are damaged, ED can occur. In addition to causing atherosclerosis, diabetes can also affect the nerves that supply the penis. Because nerves to the penis run along the prostate gland, prostate surgery (such as for cancer or an enlarged prostate) often causes ED.
Less common nerve disorders that cause ED include spinal cord injury, multiple sclerosis, and stroke. Also, prolonged pressure on the nerves in the buttocks and genital area (the so-called saddle area), as may occur during long-distance bicycle riding, can cause temporary or even permanent ED.
Other disorders
Hormonal disturbances (such as abnormally low levels of testosterone) tend to decrease sex drive but can also result in ED.
In Peyronie disease, scar tissue develops inside the penis, resulting in curved and often painful erections and causing ED.
What Is Peyronie Disease?
In Peyronie disease, inflammation inside the penis causes scar tissue to form. Because the scar tissue does not enlarge during an erection, the erect penis is curved, making penetration during sexual intercourse difficult or impossible. The scar tissue may extend into the erectile tissue (corpora cavernosa), causing erectile dysfunction. |
Drugs,
Sometimes psychological problems (such as performance anxiety or depression) or factors that decrease a man's energy level (such as illness, fatigue, or stress) cause or contribute to ED. Erectile dysfunction may be situational, involving a particular place, time, or partner.
Prolonged, painful erection (priapism) may damage the erectile tissue of the penis, leading to ED.
Evaluation of Erectile Dysfunction
An occasional episode of erectile dysfunction (ED) is not uncommon, but men who are consistently unable to achieve or maintain an erection should see their doctor because ED may be a sign of a serious health problem, such as atherosclerosis or a nerve disorder. Most causes of ED are treatable. The following information can help men know when to see a doctor and what to expect during the evaluation.
Warning signs
In men with ED, certain symptoms and characteristics are cause for concern. They include
Absence of erections during the night or upon awakening in the morning
Numbness in the area between and around the buttocks and genital area (called the saddle area or perineum)
Painful cramping in the muscles of the legs that occurs during physical activity but is relieved promptly by rest (claudication)
When to see a doctor
Although ED may diminish a man's quality of life, it is not itself a dangerous condition. However, ED may be a symptom of a serious medical disorder. Because numbness in the groin or leg can be a sign of spinal cord damage, men who suddenly develop such numbness should see a doctor right away. Men who have other warning signs should call their doctor and ask how soon they need to be seen and examined.
What the doctor does
Doctors first ask questions about the man's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause for ED and additional tests that may need to be done (see table Common Causes and Features of Erectile Dysfunction).
Doctors ask about
Drug (prescription, recreational, and illicit) and alcohol use
Smoking history
History of diabetes
History of high blood pressure
History of atherosclerosis
History of surgery (for example, for prostate enlargement, prostate or rectal cancer, or blood vessel disorders)
History of injury (for example, a broken pelvic bone or a back injury)
Symptoms of disorders of the blood vessels (for example, pain in the calves when walking or coolness, numbness, or blue color of the feet)
Symptoms of nerve disorders (for example, numbness, tingling, weakness, incontinence, or falling)
Symptoms of hormonal disorders (for example, loss of sex drive, increased size of breasts, decreased size of testes, loss of body hair, tremor, changes in weight or appetite, or difficulty tolerating heat or cold)
Symptoms of psychological disorders, particularly depression
Satisfaction with sexual relationships
Sexual dysfunction (for example, vaginal dryness or depression) in the man's partner
Even though men may be embarrassed to talk to their doctors about some of these subjects, the information is important in determining the cause of ED.
The physical examination focuses on the genitals and prostate, but doctors also look for signs of hormonal, nerve, and blood vessel disorders and examine the rectum.
The cause is sometimes clear from the history. For example, ED may occur soon after prostate surgery or beginning a new medication. One important clue is whether erections are present at night or on awakening. When erections are present, a physical cause is less likely than a psychological cause because physical causes typically inhibit erections at all times. Other factors that suggest a psychological cause are sudden development in a young healthy man, occurrence of symptoms only in certain situations, and resolution of ED without any treatment. Claudication or coolness or a blue color in the toes or feet may indicate a problem with the blood vessels such as peripheral vascular disease or vascular disease caused by diabetes.
Common Causes and Features of Erectile Dysfunction
Cause | Common Features* | Tests† |
|---|---|---|
Blood vessel disorders | ||
Blockage of arteries (peripheral vascular disease) | Claudication (painful, aching, cramping, or tired feeling in the muscles of the legs that occurs regularly and predictably during physical activity but is relieved promptly by rest) Usually risk factors (for example, high blood pressure, diabetes, or abnormal blood levels of cholesterol and lipids) | Comparison of blood pressures measured in the ankle and arm at the same time (called the ankle-brachial index) Testing for risk factors (for example, elevated blood glucose [sugar] and blood lipid levels) Ultrasonographic measurement of blood flow in the arteries of the penis |
Venous leak (when the veins in the penis cannot prevent blood from leaving the penis during an erection, as they normally do) | Erections that occur but cannot be sustained | Ultrasonographic testing of the blood vessels of the penis |
Nerve disorders | ||
Nerve damage caused by diabetes (diabetic neuropathy) | Known diabetes Sometimes numbness, burning, or other pains of the feet Sometimes urinary incontinence | A doctor's examination Sometimes electromyography and nerve conduction studies |
Intermittent episodes of weakness or numbness in different parts of the body at different times | MRI of brain and spinal cord Sometimes spinal tap (lumbar puncture) and tests of spinal fluid | |
Nerve injury during pelvic surgery or radiation therapy | Known surgery (such as radical prostatectomy) or radiation therapy | Only a doctor's examination |
Spinal cord disorders (such as tumors or injuries) | Numbness in the area between the penis and anus Usually other symptoms of spinal cord disorder (for example, numbness and weakness of legs and incontinence) | MRI of spine |
Prolonged pressure in the buttocks and genital area (the so-called saddle area), as occurs when riding a bicycle or a horse | Usually competitive athletes who bicycle for long periods Symptoms occur shortly after riding | Only a doctor's examination |
Prostatitis (inflammation of the prostate) | Pain in the pelvic or groin area and bothersome urinary symptoms, such as pain, a burning sensation, blood in the urine, having to urinate frequently, or having difficulty starting to urinate | Urine testing |
Stroke | Known stroke | Only a doctor's examination |
Hormonal disorders | ||
Hypogonadism (testosterone deficiency) | Loss of sex drive, sleep disturbances, and depression or mood changes Eventually, decreases in the size of muscles and testes, bone density, and body hair Eventually, an increase in body fat and breast size | Measurement of the testosterone level in the blood |
Round face, increased body fat in the trunk, purple streaks on the abdomen, high blood pressure, and mood changes | Measurement of levels of cortisol in the urine Sometimes blood tests | |
Severe hyperthyroidism (thyroid hormone excess) | Restlessness, increased heart rate and blood pressure, tremor, weight loss, and inability to tolerate heat | Measurement of levels of thyroid hormone in the blood |
Severe hypothyroidism (thyroid hormone deficiency) | Sluggishness, decreased heart rate and blood pressure, thickened skin, decreased appetite, weight gain, and inability to tolerate cold | Measurement of levels of thyroid hormone in the blood |
Structural disorders | ||
Peyronie disease (formation of scar tissue in the erectile tissue of the penis) | Firm tissue in the penis Often severe curving of the penis during erection Often pain during intercourse | Only a doctor's examination Usually ultrasonography of the penis to detect scar tissue |
Hypospadias (a birth defect) | Urethra located on the underside of the penis | Only a doctor's examination |
Microphallus (a birth defect) | Abnormally small penis | Only a doctor's examination |
Psychological conditions | ||
Sadness, helplessness, hopelessness, loss of appetite, and problems sleeping | Only a doctor's examination | |
Performance anxiety or stress | Full erections during sleep and when masturbating Concern about sexual performance Occurrence of ED only with certain partners or in certain situations | Only a doctor's examination |
Other | ||
Medications (see table Some Commonly Used Medications That Can Cause Erectile Dysfunction) | History of taking a medication known to cause ED | Only a doctor's examination |
Hypoxemia (chronically low blood oxygen levels) | Usually a chronic lung disorder (for example, chronic obstructive pulmonary disease) | Pulse oximetry (measurement of the level of oxygen in the blood) |
* Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present. | ||
† Testosterone level is usually measured. If the level is low, doctors measure levels of other hormones. | ||
ED = erectile dysfunction; MRI = magnetic resonance imaging. | ||
Some Commonly Used Medications That Can Cause Erectile Dysfunction
Class | Drugs |
|---|---|
Medications to treat high blood pressure (antihypertensives) | |
Medications to treat prostate enlargement | |
Medications to treat prostate cancer | |
Drugs (prescription, recreational, and illicit) that affect the central nervous system | Alcohol |
Other | Anticancer medications (most cancer chemotherapy agents) Medications (prescription and over-the-counter) with anticholinergic effects (such as many antihistamines and some antidepressants) Estrogens |
Testing
Testing is usually needed. Laboratory tests include the measurement of the level of testosterone in the blood. If the testosterone level is low, doctors measure additional hormones. Depending on the results of the history and physical examination, blood tests may also be done to check for previously unrecognized diabetes, thyroid disorders, and lipid disorders. Usually, these tests provide doctors with enough information to plan treatment.
Occasionally, doctors inject a medication into the penis that stimulates erection and then use ultrasonography to assess blood flow in the arteries and veins of the penis. Rarely, doctors may recommend the use of a home monitor that detects and records erections during sleep.
Treatment of Erectile Dysfunction
Treatment of underlying causes
Education and counseling
Oral phosphodiesterase inhibitors
Sometimes other drugs, mechanical devices, or surgery
Any underlying disorder is treated, and doctors often stop medications that may be causing erectile dysfunction (ED) or switch the man to a different medication. However, men should talk with their doctor before they stop taking any drug.
Excess weight is a risk factor for many disorders that may cause ED, so weight loss may improve erectile function. Smoking is a risk factor for atherosclerosis, so stopping smoking may also improve erectile function. Stopping or decreasing alcohol use, if excessive, can also help.
Even ED caused by a physical disorder usually has a psychological component, so doctors offer reassurance and education (including of the man's partner whenever possible). Couples counseling by a qualified sex therapist can help improve partner communication, reduce performance pressure, and resolve interpersonal conflicts that contribute to ED.
testosterone levels. These testosterone preparations can be applied daily as a patch or a gel. Testosterone nasal products and below-the-skin implants are also sometimes recommended. Men with very low testosterone levels may need testosterone injections several times per month.
Noninvasive methods (mechanical devices and medications) are tried first. Sometimes men must try the method a few times before doctors can determine whether it is effective. Usually, oral medications are tried first. Medications injected into the penis just before intercourse are effective and often tried second. Although most men prefer medications to other methods of treating ED, mechanical devices have the advantages of being highly effective and, because they are free of side effects, usually very safe. Penile implant surgery with an inflatable prosthesis is the least used, but most effective, way to achieve intercourse.
Mechanical devices and procedures
Men who can develop but not sustain an erection may use a constriction ring. As soon as erection occurs, an elastic ring is placed around the base of the penis, helping prevent blood from flowing out and maintaining the firmness of the penis. If the man cannot develop an erection, a hand-held vacuum erection device can be applied over the penis. This device draws blood into the penis by exerting a gentle vacuum effect, after which the ring is placed on the base of the penis to retain the erection. Bruising of the penis, coldness of the tip of the penis, and lack of spontaneity are some drawbacks to this method. Sometimes a constriction ring and vacuum device are combined with medication.
Medications
The primary medications for ED are oral phosphodiesterase (PDE) inhibitors. Other medications include prostaglandins that are injected into the penis or inserted into the urethra. Oral phosphodiesterase inhibitors are used much more often than other medications because they are simple to use and allow spontaneity in intercourse. Over-the-counter herbal remedies are sold for ED, but they are usually ineffective, contain hidden doses of a phosphodiesterase inhibitor, or both. The hidden phosphodiesterase inhibitor may expose the man to a medication with possible side effects.
Oral phosphodiesterase inhibitors
Priapism (prolonged erection) develops very rarely and may require emergency medical treatment. In rare instances, men have reported blindness or hearing loss after taking phosphodiesterase inhibitors, but it is not clear whether the phosphodiesterase inhibitors have been the cause.
alprostadil suppository may be combined with an oral phosphodiesterase inhibitor for men in whom oral medications are not effective.
Surgery
For some men, medications are either not effective or not acceptable (for example, due to side effects). In these men, surgery to implant a penile prosthesis may be done. Prostheses can take the form of rigid silicone rods or hydraulically operated devices that can be inflated and deflated. Penile implant surgery involves the risks of general anesthesia, bleeding, infection, and prosthetic malfunction. However, it is generally very safe, can be performed as outpatient (same day surgery), and has the highest patient and partner satisfaction rates out of all ED treatment options (over 95%).
Essentials for Older Adults: Erectile Dysfunction
Although erectile dysfunction (ED) does increase with aging, it does not need to be accepted as a normal part of aging. Rather, because older men are more likely to have medical conditions that affect the blood vessels, they are also more likely to have ED. Many older couples engage in satisfying sexual activity without erections or intercourse and may choose not to seek treatment. Nevertheless, treatment of ED can be appropriate for older men.
Key Points
ED commonly results from psychological, nervous system, or blood vessel disorders, from injury, or from the side effects of some medications or surgery.
When considering the causes, doctors consider psychological and interpersonal factors.
testosterone levels and ED, but a low testosterone level is not a common cause of ED.
Vacuum erection devices and penile prosthesis surgery are effective treatments for men with severe ED.
