Rifaximin never worked for me at all, even with adequate doses. That’s mostly why I suggested that you might want to try it on your own nickel. If it doesn’t work you can save yourself the headache of arguing with the insurance company, and if it does work you can have a more persuasive argument. It’s expensive as hell, though. My initial ulcerations were well controlled by Cipro. After some years on Cipro, symptoms began to return, though I don’t know if ulcers redeveloped at that time. Adding Flagyl got the symptoms back under control, and that’s where things stand for me. I’ve left out the list of various other things that didn’t work, though they are numerous.
Rifaximin has several on-label indications now beyond traveler’s diarrhea, including IBS. The only one that is designated for long-term use, though, is hepatic encephalopathy.