What Causes Decline Of Joint Mobility After Coming Off From Celebrex?

i m 47 and i was diagnosed with R.A. about 4 yrs ago. i ve been on celebrex,folic acid and methotrexate until recently when my DR. took me off the celebrex. she has since put me on hydroxychlor 200mg in place of the celebrex. i ve been on it since june and have noticed a decline in joint mobility and soreness. i was thinking about trying instaflex but, was wondering if it was ok to take it along with the meds i m currently taking. as per the query instructions i m 122lbs and 5 7.