Same family of drug as rifampin. Ask for a consult with an infectious disease specialist, infectious disease nurse educator, or consulting pharmacist for help managing the side effects. When rifampin makes my mouth sores too bad, I rinse/gargle like crazy with old-fashioned Listerine or Lavoris mouthwash. No others help, but this gives some relief.
As for the indigestion, my doc added Omeperazol to suppress stomach acid, and it helps.
And I find taking all 3 antibiotics at night helps me ignore the other side effects, but I do need to go to bed early or nap the next day as I sleep poorly on med nights.