Multiple Sclerosis Erectile Dysfunction: Why It Happens

Impaired nerves in the brain and spinal cord may cause ED in men with MS

Man suffering from Parkinson's disease and multiple sclerosis standing near steps. Credit: Huntstock / Getty Images

You probably don't think very much about the mechanics of an erection until you or your partner can't achieve one. Erections rely on nerves functioning properly—and because multiple sclerosis (MS) impairs nerve functioning, erectile dysfunction (ED) is one of the most common symptoms of MS reported by men. Up to 91 percent, by some estimations, experience it. But what exactly is happening in the body when a man has ED?


Types of Erectile Dysfunction

First, let's define it. While erectile dysfunction, broadly, means the inability to attain or maintain an erection that is adequate for sexual intercourse, it also can have the following characteristics:

  • Inconsistent ability to achieve an erection
  • Dissatisfaction with size or rigidity of erection
  • Having erections of short duration
  • Requiring excessive time and/or stimulation to achieve erection

These typically are not the first MS symptoms that a man experiences, but happen some years after the onset of symptoms or diagnosis.

What Causes MS-Related Erectile Dysfunction?

Erections occur when signals from the brain and local nerves cause the muscles of the penis to relax, allowing blood to flow into two chambers on the underside of the penis. This makes the penis expand and become rigid. Erections happen in response to physical stimulation of the penis or in response to erotic situations (like kissing or foreplay), or thoughts.

Erections that happen as a result of genital stimulation are using nerves in the lower part of the spinal cord, and basically “bypass” the brain – the brain does not need to send messages in order for an erection to occur.

However, erections that are in response to other kinds of physical contact or erotic thoughts or visual cues do require processing by the brain.

In this case, signals must pass from the brain along the whole spinal cord to reach the penis.

This is important, because depending on where in the brain or spinal cord the man has inflammation or demyelination, he may find that he is able to achieve erections in response to physical stimulation, but not foreplay or erotic situations—or vice versa. 

It's also important to note that male orgasm (ejaculation) is a more complicated process than achieving an erection and it requires fairly intact nerve pathways between the brain and lower spinal cord. For this reason, it's possible that a man may be able to achieve an erection, but find ejaculation much more difficult or even impossible.

Treatment is Available and Can Help 

While this is no man’s idea of a fun conversation, it's crucial for you to talk to your doctor. Many treatments for ED exist, and almost any case of erectile dysfunction can be treated to some degree, whether by tweaking your medication dosages or trying a new medication for ED. You owe it to yourself (and your partner) to ask your doctor for help. You’ll be glad you did. Getting a handle on this issue can help you feel more in control of your disease and boost your ability to experience pleasure.

The benefits of intimacy cannot be understated, especially for someone living with the stresses of an illness. 

Here are some other ways you can address the problem: 

Check Your Meds. Certain prescription medications that you might be taking for MS symptoms could be causing (or contributing to) your erectile dysfunction. These include:

  • Anticholinergics, prescribed for bladder dysfunction or diarrhea, including: propantheline, (Norpanth, Pro-Banthine) and dicyclomine (Bentyl)
  • Antidepressants, including:
    • Tricyclic antidepressants, such as amitriptyline (Elavil, Endep), desipramine (Norpramin), doxepin (Sinequan), imipramine (Tofranil-PM), nortriptyline (Pamelor).
    • Selective Serotonin Reuptake Inhibitors (SSRIs), including fluoxetine (Prozac), sertraline (Zoloft), citalopram (Celexa) and paroxetine (Paxil).
    • Norepinephrine Reuptake Inhibitors, a newer class of antidepressants, which includes venlafaxine (Effexor) and duloxetine hydrochloride (Cymbalta).
  • Marijuana: If you are using marijuana, or any of its derivatives, for MS-related spasticity, tremor or pain (or for any other reason), be aware that marijuana use can lead to erectile dysfunction.

Address Other Health Issues. While it is pretty likely that erectile problems have something to do with MS, there can be other causes of erectile dysfunction. Diabetes, high blood pressure and high cholesterol are big culprits in causing problems with erections, and need to be managed.


Turkington, C. and Hooper, K. The A to Z of Multiple Sclerosis. New York: Checkmark Books, 2005.

C. D. Beits, S. J. Jones, C. G. Fowler and Clare J. Fowler. Erectile dysfunction in multiple sclerosis Associated neurological and neurophysiological deficits, and treatment of the condition. Brain Vol. 117, No. 6, 1303-1310, 1994.

Hennessey A, Robertson NP, Swingler R, Compston DA. Urinary, faecal and sexual dysfunction in patients with multiple sclerosis. J Neurol. 1999 Nov;246(11):1027-32.


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