What causes erectile dysfunction?

An erection consists of blood flowing into the corpora cavernosa (AKA erection bodies) and being trapped there. A problem with either blood getting in or staying in causes erectile dysfunction, also known as ED.

Potential causes are many and include: vascular (high blood pressure, elevated cholesterol, diabetes, cardiovascular disease), diabetes, trauma (spinal cord injury or injury to the pelvis), neurologic disease (stroke, Parkinson's disease), radiation to the pelvis (for prostate or rectal cancer), endocrine disease, surgery in the pelvis (radical prostatectomy, surgeries for rectal cancer or bladder cancer), medication side effects (especially medications used for high blood pressure), alcohol, tobacco, cocaine, etc. Is it just the man's problem?

This is a "couples disease". Even though the problem is not psychologic (all in your head), ED causes depression, anxiety, loss of feelings of masculinity and self-esteem. This of course affects relationships and may set up a "vicious cycle" where the partner feels unattractive and so stops initiating intimacy, the man then feels unattractive, etc. This can be devastating to the couple. Very few couples can or want to give up their physical intimacy without having some problems!

Is there treatment for ED?

Luckily, there are many good treatments. These include pills, injections, penile suppositories, vacuum devices, and surgery. Surgery provides the only true cure but many men want to explore other options and may be very satisfied with them.

What about pills?

Currently, three pills are available and FDA-approved (Viagra/sildenafil, Levitra/vardenafil, Cialis/tadalafil). They are all "phosphodiesterase inhibitors" which means they act by blocking a chemical that stops erections. Viagra was introduced in 1998 (the others in 2003) and revolutionized the way that men and their partners looked at ED. With all the press and media coverage of these medications, men realized that they had a real problem and became more open to talking about it.

Keys to using pills successfully

These medications all act as "amplifiers", meaning that men still need foreplay and erotic thoughts to have an erection.

The pills may not work the 1st few times, so it is worth trying the pills several times before deciding that they do or don't work.

The pills (especially Viagra) should not be taken after a large meal, as they will not absorb as well. They should be taken before a meal in order to work well.


Generally these medications are safe. Side effects are common (around 30% of men have them) and include: headache, flushing (feeling hot), upset stomach, stuffy or runny nose, and back pain (especially Cialis). Dr. Brant has written a review on the risk of blindness with using these pills, which is a very rare side effect.

What if pills don't work?

If pills don't work or if the patient cannot tolerate them, alternatives include injections, suppositories, vacuum devices, or surgery.

What are vacuums?

A vacuum device (VED) is an external device (not a drug) that goes over the penis. When pumped, it pulls blood into the penis then a special ring is placed over the base of the penis to keep it erect.

VEDs are generally safe (although there have been some very rare but serious complications).

  • Works Well
  • No drug effects
  • Cheapest option
  • Cumbersome
  • Unnatural erection
  • Bruising or burst blood vessels
  • Penile pain
  • Pain with ejaculation
  • Numbness
  • "Hinging" or instability of erection
  • Penis may feel cold to partner
  • Poor overall satisfaction

What about injections?

Drugs may be injected directly (using a tiny needle) into the penis. Several drugs and drug combinations are available, including alprostadil (Edex, Caverject), phentolamine, and papavarine (usually given in combination as Bimix or Trimix). The patient can usually get an erection within 5-10 minutes and it should last between 20 minutes to an hour.

Injections do require training and it may be tricky to get the right dose. We always do the first injection in clinic, which helps the patient learn to do it and also gives us a good idea about the dosing. Patients are usually anxious about it but are almost always surprised by how painless the injection is. The patient will be observed in clinic to make sure the erection goes down and, if necessary, the erection is reversed. If needed, the patient returns another day to try a different dose; on the second trip, patients do the injection themselves under our supervision. Some men do not require a second visit.

It is very important to alternate injecting the left and right side of the penis and to not use injections more than 3 times per week.

  • Very effective (85%)
  • Mimics normal erection
  • Discreet
  • Risk of prolonged erection ("priapism")
  • Risk of penile scarring
  • Pain with injection (usually mild)
  • Bruising or bleeding
  • Hard to use if have tremor or poor vision or severe obesity
  • Poor long-term satisfaction (<40%)

Although injections often work well, long-term use is not common.

What about suppositories?

Urethral suppositories (AKA MUSE) contain alprostadil (see "Injections"). The pellet is given via a delivery system into the urethra (urinary channel) and dissolves there. Similar to injections, we always give the first suppository in clinic to make sure there are no problems and that the patient is comfortable doing this.

  • No needle
  • Mimics normal erection
  • Discreet
  • Gives best erection to glans (head of penis)
  • Rare scarring or prolong erection ("priapism")
  • Pain in penis (30%)
  • Expensive
  • Less effective than injections (50%)
  • Bleeding from urethra
  • Hard to use if have tremor or poor vision or severe obesity
  • Poor long-term satisfaction (<40%)

Although the suppositories are appealing, effectiveness is relatively poor and overall satisfaction is relatively low.

Is there a surgical treatment?

Although the medical treatments of erectile dysfunction or ED may provide satisfying erections, they unfortunately do not provide a long-term “cure” to the problem. They are, after all, “bandaids” for the symptoms but not a total solution.

Most men and their partners want, ultimately:

  • An erection that is rigid and satisfying for sexual activity
  • The ability to be spontaneous in their sex lives
  • The ability to predict and control how long the erection lasts and how often they can use it
  • Lack of “paraphernalia”; in other words, the erection should be natural, not associated with devices or other impediments

Currently, implants are the closest to a natural erection that the patient can achieve. When looking at satisfaction rates overall, implants are the clear winner, with around 95% satisfaction (compared to around 50% for pills, 40% for injections, 20% for vacuum devices).