About 6 months after starting pentasa I developed overnight terrible joint pain. It has been travelling through my joints every day since, and some nights/days I can barely walk or use my hands. They sent me to a Rheumatologist who said I have inflammatory arthritis associated with Crohn's disease. I'm wondering why it appeared 6 months after I got the Crohn's under control, and if Pentasa is actually the cause. I never had a drop of arthritis pain before. Neither the Gastro or Rhem. mentioned it but now I am wondering. When they tested my blood my RA factor was within normal range. C-rective protein was a bit high 5.2.