Hello As you mentioned that your mother have taken a full course of AKT -4 for 3 months . Now doctor advised rifampicin450mg+isoniazide300 mg i.e. Rcinex. Your mother is having side effects but you didn t mention type of side effects. Usually this is a tolerable medicine and don t produce much side effects. One thing I want to tell you that the compliance of patient ( cooperation ) is important in anti tubercular treatment . R cinex causes nausea, abdominal discomfort , vomiting , hyper acidity ( liver damage ,if patient have any liver disease already ). So these side effects are minor and patient can tolerate . For these side effects I prescribe pantoprazole-d ( normal dose is once in day on empty stomach ,but few patient need twice in day , all depend on condition of patient and doctor concerned). In my opinion don t take any substitute , rather give her Rcinex . For this consult your treating doctor and sort out this problem . Once again , never stop anti tubercular treatment until and unless your doctor d advice. Good luck.