How can I relieve my guinea pig of pain from arthritis?

My guinea pig chocolate is very old, and has really bad arthritis in her feet/ankle joints. This is what the vet told me a couple months ago, when she started to drag her feet and not walk properly. She never really told me how to help her, but she was happy and walking around okay.
In the past couple of days chocolate seems very unhappy
will hardly eat, and can't seem to walk.
When i pet her she does not purr and seems to be in pain.
Is there anything I can do to help her?
I read that Potters Tabritis tablets help, has anyone use that?
Or is my only option to put her down?
She refuses to eat or drink anything.