I want you to think about something here. We have had people here that were first diagnosed with IBS that were later diagnosed with MS. Please remember that I am trying to be helpful here and I am not in any way trying to minimalize what you are experiencing. First, IBS is not a disease, it is a syndrome or a series of symptoms that indicate a functional problem with the colon that either manifest as chronic diahrea or constipation or both. It could be that MS is causing your IBS. If you have a lesion on your spine or low on your brain stem, this could be effecting the nerves that are in charge of the smooth muscle contractions of your colon and large intestine. If the stool takes too long to pass through the colon, then too much water is absorbed creating dry, hard to pass stool.
I would really talk to your doctor, preferably your neuro, about your bowel problems. There are a whole host of quite serious problems that can occur with untreated bowel problems. This is typically called slow transit or colonic inertia. It is one of those MS situations that needs to be constantly monitored to insure your over-all health. Certainly, occasional laxatives will not hurt you and can prevent an impaction. You should probably consider using a fiber supplement on a regular basis. Fiber, like metamucil carries moisture down in the colon that is not re-absorbed so that the stool does not get so dry. It can truly keep you regular so you are not getting so constipated. Also, Mira-lax or polyethylene glycol can be used long term. It is an over the counter med. and for most is used short term but folks with MS can use it long term with good success. You need to make sure you are drinking lots and lots of water. Even slight dehydration can cause some horrible constipation. Also, any excercise you can manage is always helpful. Walking really stimulates colonic movement. Try short walks once to three times a day.
I am telling you all this so you can make sure you get this consistently managed. We have MS folks here that needed hospitilazation with serious impaction. Occasionally removal of part of the colon surgically is a treatment as well. It can be a very difficult to manage situation due to the fact the the colon is just not functioning as it should due to nerve problems from MS damage.
Sorry this was so long. I hope you find this helpful. Again, consider the fact that MS could be causing your IBS and that IBS is not a disease initself but a series of symptoms very possibley caused by your MS. I wish you the best of luck in managing all this.
Gretchen co-moderator MS board diagnosed with MS July 2006