Yes, fistulas are very hard to deal with, especially when they are still very painful.
To be honest, I am surprised that you are not on stronger medications. The Pentasa, as far as I know
, works better in the bowel and won't do much to help your fistula.
Perhaps you might like to talk with your doctor about
starting antibiotic therapy (such as a combination of Flagyl and Cipro), as there is some evidence that the combination of these antibiotics can help in the treatment of fistulae. You might also like to ask about
stronger medications like Remicade or Humira, which can be very helpful for people with fistulae. I don't know where you live, though, so you may need to try a few cheaper medications before you'll be allowed to use Rem or Humira.
Finally, you might like to click on the "fistulae and abscesses" link in my signature (below). There is some good information in there on living with fistulae, and treating them.
All the very best to you.
Co-Moderator Crohn's Forum. Medications for Crohn's
~~ Diet and Nutritional Therapy for Crohn's
~~ Dealing with Abscesses and Fistulae