I am on both for my lower back pain, a low dose of Ultram ER twice a day and vicodin as needed but I am going to the doctor tomorrow because the vicodin is not doing anything for my pain so I just don't take it anymore. I don't know how much the ultram works because they have tried a lot of different things but have always left me on the ultram, I don't have any negative side effects from it. Utram was one of the first meds they put me on in July when the pain hit, they have tried to many other things and I have gone from being in too much pain to stand or walk to going back to work short days. My pain is still constant but I am trying to deal with it. I know you can be on both meds at the same time so maybe they can have you try it while easing you off the vicodin. Good luck