Erectile Dysfunction

Reviewed by Andrew McCullough, M.D. and Joseph Alukal, M.D.

Erectile dysfunction (ED) is the consistent inability to achieve or maintain an erection satisfactory for sexual activity. ED is extremely common, affecting men of all ages. More than half of men over age 40 will experience some degree of erectile dysfunction. Needless to say, erectile dysfunction can have a profoundly negative impact on a man’s self-esteem, relationships and overall quality of life. The physicians of NYU Urology Associates are highly experienced in the treatment of erectile dysfunction and have helped many men and their partners manage this condition. The treatment of the condition varies from patient to patient and ranges from a simple discussion to penile implant surgery. We also recognize that no one treatment fits all patients, so we will work with you to determine the best course of action for your personal situation.

Often the first sign of erectile dysfunction is the inability to maintain an erection (loss of the erection during the sex act before orgasm). Other signs of erectile dysfunction can include decreased frequency, rigidity or duration of erections.


As men age, erectile function begins to wane. Although most men continue to be able to function throughout life, erections are never quite as good as they are at the peak of sexual function, in the late teens. Erectile function results from a complex chain of events from the brain, spinal cord, nerves and blood vessels, to the muscles in the penis. Anything that interferes with any step along the way can result in erectile dysfunction.

Every man is exquisitely aware of how well his penis is working. Small wonder the penis is considered a barometer of overall health. One Italian study found that men presenting with a heart attack experienced erectile dysfunction three years before the event. Imagine if those men had listened to their bodies and seen a doctor at the onset of erectile dysfunction. Common underlying medical causes are high blood pressure, high cholesterol, diabetes or simply hardening of the arteries. Up to 75% of men with diabetes will experience at least some degree of erectile dysfunction during their lifetime. In addition, erectile dysfunction is also associated with neurologic disorders and urinary dysfunction.


Medications. Erectile dysfunction is often an adverse effect of many commonly prescribed medications, such as drugs used to treat high blood pressure, antihistamines, antidepressants, tranquilizers, appetite suppressants, and the ulcer drug cimetidine. The abuse of recreational drugs, such as alcohol, amphetamines, barbiturates, cocaine, marijuana, methadone, nicotine and opiates can also result in erectile dysfunction.

Trauma. Trauma that affects the nerves or blood vessels of the penis can also lead to erectile dysfunction. Although trauma is sometimes associated with aggressive sexual activity and a penile fracture, some men develop scar tissue within the penis. The scar then causes shortening of the penis and a bend with erection that precludes normal sexual relations. The bending of the penis from scar tissue is called Peyronie’s disease.

Endocrine disorders. Erectile dysfunction can also reflect a hormone disorder from the brain, thyroid or pituitary gland. In very rare instances, erectile dysfunction can result in the diagnosis of a brain tumor called a prolactinoma. Low testosterone levels (hypogonadism) usually adversely affect libido and sometimes erectile function.

Psychological causes. No man is immune to the psychological ravages of erectile dysfunction. It was once thought that erectile dysfunction was purely psychological, but we know now that only one out of ten cases is purely psychological. Stress, anxiety, guilt, depression, low self-esteem, and fear of sexual failure can lead to erectile dysfunction. Men with a physical cause for erectile dysfunction frequently experience the same sort of psychological reactions. Men in their late teens and 20s are more likely to have pure psychological erectile dysfunction.


The medical history is the cornerstone to understanding the cause of erectile dysfunction. Although the choice of treatment does not necessarily vary according to the diagnosis, the physicians of NYU Urology Associates try to uncover the underlying causes of the problem. We recognize that erectile dysfunction may be an “early warning system” for other cardiovascular diseases, and we will work with your primary care physician or cardiologist if further investigation into your general cardiovascular health is warranted.

Because most erectile dysfunction has a physical rather than a psychological cause, a thorough evaluation is necessary to correctly identify the specific disease process in any given individual. In addition to asking about your detailed medical and psycho-social history and performing a physical exam and blood tests, your doctor may make use of diagnostic tools such as penile duplex ultrasound and computer-assisted penile tumescence scanning technologies, all of which are available on-site, in the NYU Urology Associates office.

Once we have established the factors underlying the dysfunction, we will work with you to determine the best course of treatment. Because no single therapy suits everyone, we strive to match the best combination of therapeutic modalities to the patient, whether it is psychotherapy, oral medication, intraurethral, penile injection therapy, penile implant surgery or even on rare occasions penile microsurgical revascularization. We also have ongoing clinical trials exploring new, state-of-the-art therapies.


Medication. Effective medications for the treatment of erectile dysfunction have been around in the US for over 20 years. In 1983, at a national meeting of urologists in Las Vegas, Dr. Giles Brindley demonstrated the results of penile self-injection in front of a live audience—with himself as the subject! We have come a long way since then, with the availability of oral medication, but realizing that 35% of men do not respond to pills, we still frequently rely on second- and third-line treatments.

  • Oral medications. NYU has been closely involved in the development and testing of the oral medications such as Viagra, Cialis and Levitra, which have revolutionized the treatment of erectile dysfunction. These medications, which promote smooth muscle relaxation in the penis, are now frequently the first treatment of choice for erectile dysfunction owing to their ease of use.
  • Intruaurethral medications. In 1997, a year before Viagra was approved, MUSE was approved by the FDA. Though infrequently used because of the popularity of oral medications, it remains an effective alternative in patients who do not respond adequately to pills, either alone or in combination.
  • Penile injections. Penile self-injections, although introduced as a generic medication in 1983 in the US, were not approved by the FDA until 1994. They remain the most effective medical treatment for erectile dysfunction, but are understandably the least popular because of resistance to the idea of penile self-injection. In injection therapy, a medication is painlessly injected into the shaft at the base of the penis, resulting in an erection.

Vacuum erection device. Vacuum erection devices have been available since 1914. A cylinder is placed around the penis and by the action of a pump, the penis fills with blood and an erection is created. The erection is held in place by an elastic device placed around the base of the penis.

Penile prostheses. Much like prostheses are used in orthopedics, so are they used in urology. For men who do not like or respond to other treatments, an outpatient surgical implantation of a penile prosthesis is a good option. During the 90-minute procedure under anesthesia, malleable or inflatable rods are surgically inserted into the penis. The concealed implant allows a man to achieve a reliable rigid erection whenever he wants. Spontaneity, so often lacking with the medications and vacuum device, is reintroduced.

Microsurgical penile revascularization. For patients younger than 40 who have ED due to traumatic injury to the blood vessels of the penis, blood flow can be restored to the penis through a bypass operation. Unlike heart bypass, this operation only works in young men. Because the blood vessels of the penis are so small (one-sixth the size of the heart blood vessels) this operation does not work in men with hardening of the arteries. This highly complex operation requires careful selection but can be very effective in restoring erections in this select group of patients.

Experimental treatments. In addition to standard treatments, several new medical therapies for ED are being studied in the Department.

  • Padmanabhan, P. & McCullough, A.R. Penile Oxygen Saturation (STO2) in the Flaccid and Erect Penis in Men With and Without Erectile Dysfunction (ED). J Androl 28(2):223-8, 2007
  • Melman A, Bar-Chama N, McCullough A, Davies K, Christ G. Plasmid-Based Gene Transfer For Treatment Of Erectile Dysfunction And Overactive Bladder: Results Of A Phase 1 Trial. Isr Med Assoc J 9(3)143-6, 2007
  • Padma-Nathan H., Montorsi F., Giuliana F., Meuleman E, Auerbach S., Eardly I., McCullough A., Homering M., Segerson T., North American and European Vardenafil Study Group. Vardenafil Restores Erectile Function To Normal Range In Men With Erectile Dysfunction. J Sexual Medicine 4(1)152-62, 2007
  • Steidle, C.P., McCullough, A.R., Kaminetsky, J.C. et al.: Early sildenafil dose optimization and personalized instruction improves the frequency, flexibility, and success of sexual intercourse in men with erectile dysfunction. Int J Impot Res, 19: 154, 2007
  • McCullough, A.R., Levine, L.A., Padma-Nathan, H.: Return of nocturnal erections and erectile function after bilateral nerve-sparing radical prostatectomy in men treated nightly with sildenafil citrate: subanalysis of a longitudinal randomized double-blind placebo-controlled trial. J Sex Med, 5: 476, 2008
  • McCullough, A.R. Rehabilitation of erectile function following radical prostatectomy. Asian J Androl, 10: 61, 2008
  • McCullough, A.R., Steidle, C.P., Klee, B. et al. Randomized, double-blind, crossover trial of sildenafil in men with mild to moderate erectile dysfunction: efficacy at 8 and 12 hours postdose. Urology, 71: 686, 2008
  • Padma-Nathan,H, McCullough, AR, et al. Randomized, Double-blind, Placebo-controlled Study of Postoperative Nightly Sildenafil Citrate for the Prevention of Erectile Dysfunction After Bilateral Nerve-Sparing Radical Prostatectomy Int J Impot Res advance online publication 24 July 2008; doi: 10.1038/ijir.2008.33
  • McCullough, AR, Steidle, CP, Kaufman,J Goldfischer ER , Klee B. Sildenafil Citrate Efficacy 8 H Postdose In Men With Mild To Moderate Erectile Dysfunction. Int J Impot Res 20:388-395, 2008