Hi, Marie, I've heard that prozac comes in a liquid form, if so, it'd be easier to slowly reduce the amount. Antidepressants are notorious for being near impossible to get off. The doctors will usually try to step you down over two weeks, but that's not realistic - I've heard of some folks taking closer to a year. If you search the web you'll probably find some groups that discuss this.
Sidebar to MS - my Mom got it in her mid-30's. In her early 50's she began an exercise program where she walked around the track at the local high school. She built herself up and got much stronger and believes the exercise is crucial to managing MS. Best, Cindy