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Erectile Dysfunction

Medically reviewed by Carmen Fookes, BPharm. Last updated on July 29, 2021.

Erection problems are common and occasionally experiencing problems achieving an erection is normal. Erectile dysfunction (ED) is defined as the consistent inability to achieve or maintain an erection that is firm enough to have sexual intercourse. Men with ED are either unable to get an erection at all, achieve an erection inconsistently, or achieve an erection briefly but not long enough for intercourse. Erectile dysfunction may also be called impotence.

Although ED is more common with age, affecting 40% to 70% of men aged 40 through 70 in the U.S., it is not considered a normal part of aging, and age is no barrier to treatment.

What Causes Erection Problems?

Obtaining and maintaining an erection depends on a number of different factors, such as a man’s circulation and blood pressure, the functioning of the nerves that supply the penis, blood levels of testosterone, weight and body fat percentage, and the amount of stress he feels from his job and personal life. A dysfunction in any one of these factors can lead to ED.

ED is most commonly caused by abnormalities of the blood vessels or nerves of the penis. This may be due to conditions such as heart disease and atherosclerosis (hardening and narrowing of the arteries), diabetes, or after prostate surgery. Other causes include:

  • Hormonal disorders, such as abnormally low levels of testosterone, (this tends to decrease sex drive but can also result in ED)
  • Structural disorders of the penis, such as Peyronie’s disease where scar tissue develops inside the penis, resulting in curved and often painful erections
  • Medications, such as alcohol, antidepressants, beta-blockers, digoxin, nicotine, opioids and illicit drugs such as cocaine or amphetamines
  • Psychological problems, such as performance anxiety or depression.

ED may also occur after spinal cord injury, multiple sclerosis, Parkinson’s disease, thyroid disorders, or stroke. Stress, illness, and fatigue can also decrease a man’s energy level and cause or contribute to ED and ED may also be situational, only occurring in a certain place, at a particular time or with a particular partner. Temporary ED has been linked to long-distance cycle riding, from prolonged pressure on the nerves in the buttocks and genital area.

Premature ejaculation (when a man orgasms and ejaculates too quickly) may also be caused by physical or psychological issues but is not the same as ED. See here for more information about premature ejaculation. ED does not usually affect male fertility with regards to sperm count or quality.

How is Erectile Dysfunction (ED) Diagnosed?

Because persistent ED may be a sign of an underlying disorder, such as heart disease or a nerve disorder, men with consistent ED should see their doctor for further evaluation, particularly if a man has:

  • A lack of erections during sleep or upon awakening
  • Numbness in the perianal area (between the buttocks and genital area)
  • Painful cramping in the leg muscles during physical activity, that resolves upon rest.

Your doctor will first ask questions about your symptoms, medical, psychological, surgical and medication history.  Your doctor will also need to know about your drug and alcohol use, smoking history, and if you have ever had a back or pelvis injury in the past because these can all affect erectile function.

A physical examination is usually performed to look for any structural abnormalities and to check the size of your prostate. Laboratory tests usually include testosterone levels but further tests, such as urine screens, blood tests, penile ultrasounds, or nocturnal penile tumescence (NPT) (a test that determines if you are having nighttime erections) depend on the results of other tests or if your doctor suspects any underlying conditions.

How to Treat Erectile Dysfunction (ED)

Effective treatments for ED are available and your doctor will tailor your treatment depending on the cause of your ED or associated conditions. In addition to lifestyle changes and counseling, treatments for ED include:

  • Oral medications
  • Injections into the penis or pellets that are inserted into the urethra
  • Vacuum devices
  • Surgery.

Your doctor will advise you of the benefits and possible side-effects or complications that may occur with each therapy.

Lifestyle changes and counseling

Research has shown that inactivity and excess weight is a risk factor for many different conditions that may lead to ED so you should exercise daily and lose weight if you are overweight. Smoking also increases your risk for atherosclerosis which can contribute to ED, so attempts should be made to quit smoking and avoid illegal drugs. Limiting alcohol use can also help. Your doctor will also consider all the medications you currently take and determine if any of them are contributing to your ED and if there are any possible alternatives that may be given instead.

Reassurance and education may help address any psychological component of the ED and both the man with ED and his partner should be counseled together. This may improve relationship communication, reduce performance pressure, and resolve interpersonal conflicts that contribute to ED. Work with your doctor to manage diabetes, heart disease or other chronic health conditions and seek help for anxiety, depression or other mental health concerns. Take steps to reduce stress. See your doctor for regular checkups and medical screening tests.

Oral treatments for Erectile Dysfunction (ED)

Oral phosphodiesterase inhibitors are considered the preferred drugs for ED in men without contraindications. These block the action of an enzyme known as cGMP-specific phosphodiesterase type-5 (PDE-5). This enzyme breaks down cGMP, a substance that induces smooth muscles to relax. Blocking PDE-5 means increased levels of cGMP within the smooth muscles which promotes muscle relaxation and vasodilation (a widening of blood vessels).

High levels of PDE-5 are found in the penis, lungs, and retina. Oral PDE-5 medications used for ED increase blood flow to the penis, and there are four agents currently available:

Although each agent works in the same way, they differ as to how long their effect lasts, their side effects, and their interactions with food. Tadalafil has the longest lasting effect (up to 36 hours) and is available as a lower strength tablet that can be taken on a daily basis, eliminating the need to 'plan' for sex.

Most PDE-5 inhibitors work best when taken on an empty stomach and at least 1 hour before sexual intercourse. Side effects include low blood pressure, flushing, vision abnormalities (including abnormal color perception), and headache. Priapism (prolonged erections of more than four hours duration) have been reported rarely but may require emergency medical treatment. Oral PDE-5 inhibitors can interact with some medications such as nitrates (prescription or recreational amyl nitrate), causing severe hypotension (low blood pressure) to develop. PDE-5 inhibitors may not be suitable for men with angina, chest pain, or other heart conditions, liver or kidney problems, blood or bleeding disorders, stomach ulcers, certain eye conditions, or with a physical deformity of the penis (such as Peyronie's disease).

Many over-the-counter herbal remedies are marketed for ED; however, their effectiveness is not guaranteed and investigations have also shown some may contain hidden PDE-5 inhibitors, which may be contraindicated in some men.

Men with low testosterone levels may benefit from supplemental testosterone.

Penile Injections and Urethral Pellets

Prostaglandin E1 (alprostadil) is available as a penile injection and transurethral pellet (which is a very small pellet that is inserted into the opening of the penis). Alprostadil is used immediately before sexual intercourse and an erection should occur within 5 to 20 minutes and last up to 60 minutes. It may be used by itself or combined with papaverine and phentolamine.

Common side effects may include mild pain in your penis, urethra, or testicles; redness of the penis; or warmth or burning in your urethra. The partner of the person who has used alprostadil may also experience burning, itching, or irritation of body areas that come into contact with his penis.

Mechanical Devices

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 a 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 drug therapy.


For some men, drug therapy is not effective or acceptable. 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. Both involve risks associated with general anesthesia, infection, or prosthetic malfunction.

See Also

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.