Sister has chronic back pain and Dr. has her take oxi-20mg. And now she is having dental extracting being done and it caused infection and ear pain and mouth pain. So they added fenty. 12 mg. Patch for every 72 hours. The patch isn't doing it for pain relief in the back if needing the oxi- 20 mg. Does she continue as normal ? One tablet every 8 hours? She's 145 lbs. Thx