This is a tricky one.  Is she over-medicating with RA medications or pain pills that she takes for RA.  It is so important that you talk with her concerning this as soon as possible.  It may be that the doctor has been uping her dosage in the middle of a prescription which would lead to her running out sooner.  But if this is not the case she needs to seek help immediately!  Taking more of any medication than prescribed can be very dangerous!  Especially if she is taking too many pain pills which unfortunately could be addictive to.  I can not stress the importance of you speaking to her about this and immediately!  I know it can be scary to confront a loved one, especially one that is in pain, but a simple talk could save her life.  If she will not talk to you in regards to this, contact her doctor.  He may not be able to release any medical information to you, but he needs to know if she is taking too much of a prescribed medication.  Good luck and best wishes!