Hi Frogjive!
I'm on both LDN and Pentasa, and that combination seems to be working for me thus far. I've been on 4.5mg from day one, and aside from a few vivid dreams in the beginning, there haven't been any other side effects to speak of. I know some people who have taken LDN have spoken about it getting worse before it gets better -- while that wasn't the case for me personally, I will say that the improvement process was slow. I started out when I was already doing OK (not 100%, but at least better than I had been doing), and the change was so gradual I hardly noticed it at all. Only when did I think back to how much worse I was months ago did I realize that LDN was helping me. I just had an MRI and although I seem to have a bit of scar tissue, there is currently no active inflammation present.
Hope this helps somehwat!!