May I ask some questions?
First of all, you want to be careful giving Rimadyl when the liver enzymes are elevated, so have you tried any other pain medications?
Is the pain mostly around eating?
Any vomiting or diarrhea?
How does she exhibit that he is painful? What signs do you see?
How old is she?
have you tried giving pepcid before meals? Sometimes acid can be very uncomfortable and pepcid is a very safe medication. You would give it about 30 minutes before feeding. How much does she weigh and I can tell you what her dose would be?
Also, there is a medication called carafate that is a coating agent used in dogs with suspected gastric ulcers. You may want to ask your vet about trying this.
Rimadyl only lasts about 12 hours, so I would expect any pain relieving properties of it to wear off after that amount of time.
The pepcid (yes pepcid AC) won't hurt anything. I would try it. Give 5mg (1/2 of a 10mg tablet) every 12 hours about 30 minutes before feeding...
And with the history of taking rimadyl and prednisone, I would ask about the carafate because gastric ulcers are a common side effect of both of those medications and the carafate would act to coat the stomach to allow it to heal. Ulcers can be very painful and can wax and wane in symptoms. Plus, the carafate is very safe too... but if you start giving that and pepcid, you need to space them out by about a hour when you give them or they will neutralize each other and neither one will work...
Does that help?
Let me know if you have any additional questions.