If your mother has Arthritis, she needs to see a Rhuematologist. I was diagnosed with RA (Rheumatoid Arthritis) over 30 years ago. There is probably not enough room in this reply box to list all the medications, I have been treated with for this condition. All I can tell you is some work, some do not. Some work for a while and then stop. The best thing to do is get her an appointment ASAP with a Rhuematologist. Chuck's suggestion of writting down your questions prior to the visit is a great idea. Also, the doctor should be open to you or your mother calling the office after your visit, with any new questions either of you may have.
P.S. I was just kidding about all the medication for which my RA has been treated. I think I could list them, but "really" there are quite a lot, and it really would not do you any good to name them. What works or worked for me, may not help your mom.
Good Luck. I'll keep you both in my prayers