For men, complaints of erectile dysfunction are the most common sexual problem in MS, and the most frequent reason men seek sexual help. Viagra® is the first drug approved by the United States Food and Drug Administration that is orally administered for impotence. Sildenafil works by blocking a chemical in the erectile tissues that causes erections to become flaccid. It doesn't improve libido, but is helpful in maintaining erections when they occur. It is typically taken an hour before anticipated sexual activity, and is effective for four hours or more following ingestion. Clinical trials of Viagra® in MS have been conducted, with both men and women. Although the findings have not been published to date, positive effects have been reported from the studies. Viagra® is associated with increases in frequency of sexual intercourse, and in maintaining satisfactory erections in MS. When there is significant conflict or distress in a relationship, counseling is necessary to restore intimacy and improve communication.

Viagra® is not advisable for persons taking nitrate-based medications, since a medication interaction may cause a sudden and potentially dangerous reduction in blood pressure, even if the nitrate medications are taken occasionally. It is important to take Viagra® only when prescribed by a doctor who knows all of the treatments and medications you are taking. Side effects of Viagra® in the clinical trials were relatively minor and infrequent, with headache, facial flushing, indigestion, dizziness, and blue-green visual aura being reported.

There are a number of other oral medications in clinical trials for erectile dysfunction, including Vasomax® and IC351®. These medications work by relaxing smooth muscle in the penis, which enhances the ability to develop and maintain erections. Further testing is required on these medications, and it is not yet known whether they will be helpful in MS. Other medications being tested work directly in the brain to increase neurotransmitters that facilitate erectile capacity.

Another medical approach available for erectile dysfunction in MS involves the injection into the penis of medications, such as alprostadil (Prostin VR®) or papaverine, which increase blood flow and help maintain blood volume within the spongy erectile tissues. Auto injectors are available that work with a simple push-button mechanism. The injection usually causes only mild discomfort, and is described as similar to being flicked by a rubber band. Side effects are minimal for most users, if instructions by the urologist or prescribing physician are carefully followed. Overly prolonged erections, called priapism, are a side effect that can damage the tissues of the penis. It is crucially important that a man never have an erection for more than four hours. If this occurs, he must see a doctor immediately, to be given an injection to reduce the erection. A second potential side effect is scarring at the injection site, which can occur in 7 - 10 % of men.

Alprostadil can also be used via urethral suppository (MUSE®), in addition to the penile injection. In this approach, a small plastic applicator inserts the drug into the urethra. The drug is absorbed into the penile tissues, and stimulates a satisfactory erection in most men with erectile dysfunction. Approximately one third of men trying the drug report some penile discomfort with use, and priapism can occur in rare instances.

The direct application of alprostadil to the surface of the penis in the form of a cream or gel is undergoing testing. Alprox-TD® or Topiglan® is applied directly to the penis, and is absorbed rapidly. Preliminary data indicate that it is helpful in non-MS populations, although further testing is needed and it is not yet approved by the US Food and Drug Administration.

One noninvasive device that aids in erections is the vacuum tube and constriction band. With this method, a plastic tube is fitted over the flaccid penis, and a suction pump or tube is operated to create a vacuum that subsequently produces an erection. A latex band is slipped from the base of the tube onto the base of the shaved penis. The band maintains engorgement of the penis for sexual activities. The band can not be used for more than 30 minutes, or damage can occur to penile tissues. For persons who can attain erections readily, but have difficulty maintaining them, the constriction band alone can be used with satisfactory results. Patient satisfaction with this device is generally quite high. This product is now available without a prescription in the United States, although consultation with a urologic nurse or physician is advised to make sure the product is used safely. See the end of the article for ordering information.

There are a number of sexual aids available by mail order that do not require a physician's prescription. Strap-on latex penises, some of which are hollow and can hold a flaccid or semi-erect penis, are preferred by some. Strap-on, battery-operated vibrators in the shape of a penis are also available.

More invasive forms of treatment for erectile problems include the surgical implantation of a penile prosthesis. A penile prosthesis is a mechanical device designed to give a man with erectile dysfunction the option of having an erection. There are two types of penile prostheses, semi-rigid and inflatable. With the semi-rigid type, a flexible rod is surgically implanted in each of the erection chambers (corpus cavernosa) of the penis. These rods can be bent upward when an erection is desired and bent downward at other times. Following insertion of the rods, the penis remains somewhat enlarged, with a permanent semi-erection.

With the inflatable type of prosthesis, fluid is pumped from a reservoir behind the abdominal wall into expandable cylinders inserted into the erection chambers of the penis. The fluid causes the balloons to inflate, resulting in an erection. The man pumps the fluid into the chambers when he desires an erection and transfers the fluid back into the reservoir when he no longer wants the erection.

A spouse or long-term sexual partner should be included in the decision to get an implant, as well as the selection of the type of prosthesis to be used. Extensive pre-surgery consultation with a urologist or physician familiar with MS will help to ensure that the man and his partner have realistic expectations after the surgery. Many men experience normal erectile sensations and normal orgasm following implant surgery.

There can be significant side effects and complications of implant surgery, however. Because many other alternatives for erectile dysfunction have become widely available, this option is utilized only as a "last resort" for men in which less invasive procedures have failed.

In coping with erectile dysfunction, it is very important to include your sex partner in the discussion, if you have a long-term relationship. This will enhance intimacy by allowing both partners to learn and explore together. If partners feel inhibited about talking through these issues, counseling with a mental health professional who is knowledgeable about MS can help.