What is the normal process for an erection?

Superficially, the process of attaining and maintaining an erection is relatively simple. The penis is made up of 3 tubes, the 2 major ones being called the corpora cavernosa. These tubes run along the length of the penis and are surrounded by tough fibrous capsule called the tunica albuginea of the corpora.

An erection happens when the message is sent through nerves in the lower spinal cord. These nerves tell the arterial blood vessels entering the spongy tissue of the penis to relax and allow more blood into the penis. At the same time, flow of blood out of the penis is relatively blocked off so that the penis fills with blood and stretches the capsule (tunica albuginea of the corpora) causing rigidity.

Underlying the erection process is a series of chemical reactions and other processes including hormonal balance.

What is erectile dysfunction?

Erectile dysfunction is the inability to achieve and/or maintain an erection that will allow sexual activity with penetration.

Erectile dysfunction should not be confused with low libido (lack of interest in sexual intercourse), anorgasmia (the inability to reach orgasm or ejaculate), premature ejaculation (ejaculation too early) or retrograde ejaculation (ejaculation into the bladder). These problems are different and required a different treatment regimen.

How common is erectile dysfunction?

Erectile dysfunction is extremely common. About one in three men over the age of 50 will experience erectile dysfunction. With increasing age, erectile dysfunction becomes even more common.

What are the causes of erectile dysfunction?

Erectile dysfunction can be the 1st sign of a serious medical problem. These medical problems include diabetes, hypertension, heart disease, depression and kidney disease. 

Other causes of ED include medications, illicit drugs, neurological conditions and various psychological causes.

Psychological causes include performance anxiety, sexual upbringing, relationship issues, employment and financial pressures, depression and psychiatric disease.

Conditions that can interfere neurologically include Parkinson’s disease, Alzheimer’s disease, spinal cord injury, multiple sclerosis, peripheral neuropathy (especially from diabetes), pelvic surgery (bowel, prostate surgery) and pelvic floor injuries/pelvic fractures.

General medical conditions that can interfere with penile erection include hypercholesterolaemia, diabetes, hypertension, cigarettes and chronic renal failure. These conditions can lead to problems with blood vessels (atherosclerosis). Blood vessel narrowing leads to decreased blood flow to the penis but more importantly, can also be a problem throughout the body. For example, heart disease/coronary artery disease may initially present with erectile dysfunction.

Treatment of other medical problems can also cause erectile dysfunction. Medications used to treat hypertension, depression, hypercholesterolaemia, psychiatric conditions and prostate cancer may inhibit erection function. Illicit drug use and alcohol may also weaken erections.

Rarely hormonal abnormality such as low testosterone, high prolactin levels and thyroid disease can cause ED.
Penile problems such as Peyronie’s disease or scars after penile injection therapy can also lead to long-term ED.

What treatment options are available to treat ED?

The treatment options available to treat ED include the following (in a stepwise approach)

1. Adopting a healthy lifestyle. This is general advice I give to all men, for it may improve other aspects of medical health as well as erection function. This includes advice to start a resistance and aerobic exercise program, to choose a healthy balanced diet, to reduce the amount of unhealthy dietary fats (saturated and trans fats especially), encouragement to eat a wide range of fresh vegetables and fruits, encouragement to eat more dietary fibre, to incorporate traditional low-cost dietary soy products, to try to eat some healthy fish products (increase omega-3 intake) and to obviously have a healthy lifestyle by stopping smoking, moderating alcohol intake avoiding illicit drug use and controlling other medical conditions such as hypertension and diabetes.
2. Using oral medications such as Sildenafil (Viagra), or Tadalafil (Cialis) . These tablets do not actually cause an erection but enhance the normal body response to nerve stimulation from the spinal cord. They are all equivalent in efficacy but some men find one brand works better than another. They should ideally be taken an hour to 2 hours before sexual intercourse is attempted. The drugs are differentiated by their ability to be taken with or without food/alcohol and by the time frame for which they will work. Some formulations can be taken on a daily basis and therefore, allow for spontaneous intercourse.
3. Penile injection therapy
4. Surgical treatments such as penile implant.

The oral medications are well-tolerated. Common side effects include gastrointestinal upset, headache, nasal congestion, visual change (blue tinge) and occassionally back pain. There is a very small risk of priapism (prolonged painful erection). The main danger with PDE 5 inhibitors are the potential side-effects when used with nitrates, medicines such as glyceryl trinitrate (GTN).  These medications are used to treat angina and other heart conditions.

The PDE 5 inhibitors should also not be taken if one has a history of

• heart or blood vessels problems that make sexual intercourse inadvisable
• heart attack or stroke within the last 6 months
• uncontrolled hypertension or hypotension 
• using recreational drugs such as “poppers” or “amyl”. These drugs contain nitrate like equivalents.

The PDE 5 inhibitors should be trialled/used on multiple occasions, in a short time period, before they are classed as having failed to achieve a response. I tell men that they should at least try 6 to 8 tablets, on separate occasions, if they are using an on-demand regimen.

In the end, this is goal directed therapy and the ultimate aim is to achieve a satisfactory erection. The causes of erectile dysfunction are difficult to elucidate and often do not alter management. This is because many of the causes of ED are irreversible.

Please ask further questions regarding your present treatment and the options available to you to resolve your erectile dysfunction.