I realize that this is an old post, but it's great to finally meet SOMEONE with both bi-polar d/o AND Rheumatoid Arthritis...I benefit from lithium as well, but I can't take lithium while taking ANY NSAID drug, such as motrin, naproxyn etc. and these types of drugs are very critical in treating RA, or swelling in general.
I am fighting for disability, since I have to give up one of the drugs that is best to treat my conditions. I don't know much about getting flares b/c of meds - I get them randomly and from weather.... Best of luck to you.