Re: Worried about Mom.....
Could you make a dr appt for her and then call the day off and tell her you're worried to death about the stomach problems and you'll be over to get her shortly and take her. Don't mention the opiate use to her, just express concern about her stomach problems. Make sure you go back with her when the dr sees her. Try to tell the dr about her opiate addiction beforehand and let the dr bring it up to her.
Sometimes the children have to take the roll of a parent on the parents behalf. Life shifts like that sometimes. My Mom was a RN and when she had breast cancer a few yrs ago, I took her for all appointments and and went back in the exam room with her. She's sharp as a tack, but was not outspoken enough with the doctor. Her surgery took to long from the time she was diagnosed till the surgery. Then when she returned post op from lumpectomy the dr told her he would have to go back in because he didn't get clear margins. If I had not spoke up about the lenght she had to wait for the original surgery, she would have been waiting along time again. (HMO).
They got her in for the 2nd surgery 3 days later.
I guess my point is that our parents need an advocate sometimes and it's usually the daughter that has to take action. I hope you'll consider my suggestion, if your mother is not too ornery to go. I know some can be very stubborn.