Drugs — A large number of drugs that affect the nervous system and some that lower testosterone levels or inhibit testosterone action can cause ED. Opioids that are taken for chronic pain can also cause ED.

Psychologic causes — Depression, performance anxiety, and lack of focus are common causes of psychogenic ED.

● Depression – Loss of libido and lack of interest in sexual activity are common symptoms of depression. ED is, in itself, a depressing experience for many men. Many men choose to accept a decline in sexual function as a natural consequence of aging. Because of shame or embarrassment, they do not discuss this problem with their health care provider. This is unfortunate because it is often possible to determine the cause(s) of sexual problems and many options are available to treat ED.
● Performance anxiety – Performance anxiety may develop in men who suddenly experience one or more erectile failures during intercourse. The focus of the sexual act shifts from a sensual experience to one filled with anxiety. During later attempts to have sex, the inability to acquire and maintain an erection becomes the focus of the sexual experience.

Diagnosis — In order to determine the cause of the dysfunction, a health care provider will take a sexual history, perform a physical examination, and order blood tests to determine if conditions such as diabetes or low testosterone levels are contributing to the sexual problems. Sometimes more specialized tests, such as evaluating penile blood flow with ultrasound during a pharmacologically induced erection, can provide useful information.
Sexual history — The clinician will ask the patient personal questions about his sex life to help determine the cause of the condition. It is important that the patient answer the questions honestly and provide as much detail as possible.

The clinician will want to know if:

● ED developed slowly or happened suddenly
● There are erections during the night or in the morning when he first wakes up
● There is similar ED with masturbation
● There are interpersonal problems with a spouse, girlfriend, or sexual partner
● There are any risk factors for impotence, such as a history of smoking, diabetes, high blood pressure, high cholesterol levels, alcohol or drug abuse, or depression.

Physical examination — In addition to doing a basic physical examination, the clinician may:

● Check pulses in the groin and feet
● Check the breasts for abnormal swelling, a condition called gynecomastia
● Examine the penis

● Check the testicles’ size and for any abnormal testicular masses
● Check the prostate.

Testing — The clinician may order tests to measure levels of testosterone, prolactin, and thyroid hormones in the blood. Abnormally low testosterone, elevated prolactin, and either low or elevated levels of thyroid hormones can cause sexual problems. All men with sexual problems should have blood tests.

If a hormonal problem is present, these tests may help to diagnose a more serious problem, such as growth in the pituitary gland or malfunction of the gonads. Even the most experienced clinicians cannot determine hormone levels by asking about the history and performing a physical examination; blood testing is necessary.

Treatments — The goal of treating ED is to enable a man to achieve and maintain an erection so that he can have sexual intercourse. Depending upon the cause of ED, treatment may include one or more of the following:

Obesity — Weight reduction and improvement in lifestyle can improve libido and erectile function in some men.

Drugs — When possible, it may be useful to use alternative medications to treat hypertension and pain. Stopping smoking and reducing or stopping alcohol can be beneficial.

Phosphodiesterase-5 inhibitors — Phosphodiesterase-5 (PDE-5) inhibitors work by increasing chemicals that allow the penis to become and remain erect. They help a man to achieve an erection after sexual stimulation, but the medication does not increase sexual desire.

PDE-5 inhibitors are effective in restoring potency in up to 70 percent of men. They work best in men with psychogenic impotence, though they can be used in men with other types of ED as well. In men with conditions that affect the blood vessels (such as diabetes), PDE-5 inhibitors are effective in many patients. The success rate in men who have undergone prostate cancer surgery is between 25 and 30 percent.

Sildenafil — Sildenafil should be taken on an empty stomach one hour before planned sexual intercourse. Its effect lasts for approximately four hours; this refers to the timeframe that erection is possible if sexual stimulation occurs, not the duration of the erection. Only one dose should be taken per 24 hours.

Vardenafil, tadalafil— Vardenafil, tadalafil are PDE-5 inhibitors used to treat ED. Like sildenafil, men who take vardenafil may have an erection (in response to sexual stimulation) as soon as 30 minutes and for up to four hours after taking a vardenafil tablet (this refers to the timeframe that erection is possible if sexual stimulation occurs, not the duration of erection). No more than one dose should be taken per 24 hours.

Men who take tadalafil may have an erection within one hour (in response to sexual stimulation) and may be able to experience an erection (in response to sexual stimulation) up to 36 hours after each dose (this refers to the timeframe that erection is possible, not the duration of erection). No more than one dose should be taken every 24 hours. Tadalafil can also be taken every day as a low-dose pill. Daily tadalafil can be helpful for men who respond poorly to an “on demand” PDE-5 inhibitor. It also may be prescribed for men with lower urinary tract symptoms (LUTS) as well as ED.

Use of PDE-5 inhibitors

● Side effects – Side effects of PDE-5 inhibitors include headache, flushed (red) skin, indigestion, and dizziness. Sildenafil may cause distorted (blue-tinged) vision. Side effects are generally short lived and resolve spontaneously.
● Drug interactions – Men who use nitrates (nitroglycerin) in any form, either on a regular basis or only as needed for chest pain, should never use PDE-5 inhibitors. Taking PDE-5 inhibitors and nitrates can lead to dangerously low blood pressure. PDE-5 inhibitors do not cause heart attacks.

A man who has used a PDE-5 inhibitor and then develops cardiac problems and requires nitrate medications should NOT use the PDE-5 inhibitor in the future. Men who develop chest pain should contact their health care provider or go to an emergency department immediately. If a man takes tadalafil, he should wait at least 48 hours before taking a nitrate.

Certain medications (including erythromycin, ketoconazole, protease inhibitors, rifampin, phenytoin, and grapefruit juice) can alter the duration of time that sildenafil, vardenafil, and tadalafil remain in the blood stream, which can cause additional side effects. A health care provider or pharmacist can provide specific information.

Medications such as doxazosin and terazosin, used to treat LUTS caused by an enlarged prostate (called benign prostatic hyperplasia [BPH]) should be used very cautiously with any of the PDE-5 inhibitors; the combination of these drugs can cause very low blood pressure. It is not known if tamsulosin is safe to take with sildenafil or vardenafil. (See “Patient education: Benign prostatic hyperplasia (BPH) (Beyond the Basics)”.)

Safety — It is not yet proven that sildenafil is safe for these groups:

● Men who have had a heart attack, stroke, or life-threatening irregular heartbeats (called arrhythmia) within the last six months
● Men with untreated low or high blood pressure
● Men with retinitis pigmentosa, a progressive eye disorder that can lead to blindness

Resuming sexual activity after a prolonged period of inactivity is similar to beginning a new exercise routine. Men considering a PDE-5 medication should be able to participate in an activity that is approximately equal to the energy required for sex (eg, walking two to four miles per hour on a flat surface). The health care provider may recommend exercise treadmill testing to ensure that sexual activity will be safe.

Nonarteritic ischemic optic neuropathy or NAION, a condition associated with loss of vision, has been reported in a few men who have taken sildenafil and tadalafil. Most of these cases occurred in men with underlying nerve or blood vessel disease. Contact your health care provider if you are taking a PDE-5 inhibitor and develop sudden vision loss in one or both eyes.

Purchasing medications for erectile dysfunction — A number of sources claim to sell medications such as Viagra, Cialis, or herbal supplements for ED through the internet or by mail for a reduced cost, often without a prescription. These sources are not known to be safe or reliable, and it is not possible to know whether the pills from these sources contain the actual drug or are counterfeit. Consumers are strongly cautioned to avoid potentially unreliable sources for any medication. Community pharmacies or reputable web-based pharmacies are the most reliable source for all types of medications.

Penile self-injection — With penile self-injection, the patient injects a medication (alprostadil or papaverine) into the corpora cavernosa (the two chambers of the penis that are filled with spongy tissue and blood). This causes an erection by allowing the blood vessels within the penis to expand so that the penis first swells and then stiffens to create a fully rigid erection. The erection created by penile injection occurs without sexual stimulation (different from the erection that occurs after sildenafil, vardenafil, or tadalafil).

It takes some training for men to feel comfortable with this type of therapy. Under the guidance of urologists, men are shown how to make the skin on the penis sterile and how to inject the medication properly. Although this treatment works well for erections, many men eventually stop using it because of discomfort from the injections.

Side effects — Pain is the most common side effect. Men often say that this is the reason they discontinue this type of treatment.

There is also a small risk that the penis will remain erect after intercourse. This occurs in 6 percent of men who use alprostadil and approximately 11 percent of those who use papaverine. Prolonged erection, called priapism, that lasts longer than four to six hours is a medical emergency. A health care provider should be contacted immediately. An emergency procedure must be done as soon as possible to empty the blood that is trapped in the penis. An erection that lasts longer than 48 hours often results in scarring of the tissue inside the penis.

Intraurethral alprostadil (MUSE) — This treatment uses the same medication (alprostadil) as penile self-injection. Instead of injecting it, the man inserts a device with an alprostadil pellet (suppository) into the urethra. The urethra is the opening in the center of the penis from which urine flows. The alprostadil is then absorbed into the erectile bodies (corpus cavernosum) to create an erection.

Side effects — Side effects include pain as the blood vessels in the penis widen and swell to create the erection. Problems like prolonged erection and scarring on the outside of the penis are less common than with self-injection therapy.

Vacuum-assisted erection devices — There are several products on the market that involve placing the penis in a plastic cylinder and creating a vacuum around the penis. This increases blood flow into the penis. A rigid ring is placed at the base of the penis (near the body) to hold the blood inside the penis, allowing it to remain erect. Vacuum devices successfully create erections in as many as 67 percent of patients. Satisfaction with vacuum-assisted erections varies between 25 and 49 percent.

Vacuum-assisted devices require that a man be able to hold and pump the unit. It may take a week or more for the device to work effectively. After a man is accustomed to using the device, he can usually create an erection that is rigid enough for penetration and sexual intercourse. He will not be able to ejaculate because the ring that holds blood in the penis also compresses the urethra, preventing semen from exiting. The ability to have an orgasm is not affected by the ring.

Penile prostheses — A penile prosthesis is a device that is surgically implanted and inflates to allow the penis to become erect. Penile prostheses can be semi-rigid rods or inflatable cylinders that are inserted into the corpora cavernosa. Penile prostheses are used less frequently because of the popularity of PDE-5 inhibitors and penile injection therapies. For men who do not respond to these therapies or who find vacuum erection therapy distasteful, penile prostheses are an option.

Side effects — Side effects of prosthetic devices include the possibility of infection, erosion, pain, and mechanical failure. Mechanical failure may require surgically removing the prosthesis and implanting a new one.

Revascularization — Revascularization is reserved for young men who have experienced pelvic trauma. Revascularization of penile arteries is rarely successful for chronic vascular insufficiency.

Testosterone replacement therapy — Testosterone therapy is prescribed if a man’s testes do not make enough of the hormone testosterone. It is of no benefit in improving sexual function in men whose bodies make normal amounts of testosterone. Testosterone levels are determined with blood tests.

Men with low blood testosterone levels may have diminished libido (sex drive), ED, decreased muscle mass, increased fat, and they are at increased risk for thinning of the bones (osteoporosis). Treatment is designed to increase a man’s testosterone level, libido, erectile function, and muscle mass; bone density usually improves as testosterone levels return to normal.

Psychotherapy and psychoactive medications — Depression and anxiety can cause ED. Often these problems can be treated using psychological counseling, antidepressant drugs, or both. Referral to a certified sexual therapy counselor may be helpful for men with performance anxiety.

Medications are used to treat both depression and anxiety. They are very effective, though some (especially those of the serotonin reuptake inhibitor [SSRI] class) can cause decreased sex drive and ED. On the other hand, some antidepressant drugs can cause delayed ejaculation, which can be helpful for men with premature ejaculation.