Switched from Lialda to Pentasa because of insurance

I have recently become eligible for Medicaid. I had no insurance for about 5 years. I was seeing my gi doc and rheumy about once a year, in order to get my med prescriptions renewed. I was able to get all of my medications through patient assistance. I had been taking Lialda, 4 -800 mg tabs per day, 150 miligrams of azathioprine, and Cimzia for the RA. My insurance wouldn't pay for Lialda, so my doctor switched me to pentasa. Now, after about a month I'm starting to get a flare. I haven't seen any bleeding yet, but I have diarrhea. Could it be the change to pentasa from Lialda? I've heard that it is more effective for Crohn's than for UC.

Does anyone know the difference in these medications? I used to take Asacol, but switched to Lialda because they had a better patient assistance program. I didn't see a difference.

I was taking 4/ 1.2 gm Lialda per day. Now I'm taking 8/ 500 mg capsules of Pentasa per day. I'm also taking 150 mg of generic Imuran (azathiprine) daily. For my RA, I'm taking an injectable, Cimzia which is supposed to also be helping the UC. Plus my heart meds and I'm taking handfulls of pills daily. I am getting them fro Exact Scrip, and they put them in little packets, on a roll that you peel off and open 4 times a day. That seems like a lot of medicine, even to me. Yet I'm still having issues with diarrhea and cramps. No bleeding, yet, though!