Imuran (or 6mp, its essential twin) ratchets down your immune response slightly to reduce inflammationa and damage in the GI tract. It does take 3-6 months to reach full effectiveness, and the frequent blood tests are designed to make sure it does not tip you over into immune deficiency, though that is a fairly rare reaction which can be easily reversed simply by stopping the drug. Continuing on your other meds for a time will bridge the gap between starting Imuran and the time it reaches full potency for you. And as has already been noted, many many people here have had very good long term results from the Imuran/6mp family of medications. So give it c chance before stepping up to something even more potent like Remicade or Humira.