I have a couple of questions for you and your doctor. If you are chronically dehydrated and this puts you at a higher risk for the serious side effect of bone marrow suppression with MTX, why not consider azathioprine (Imuran) instead?
Also, why injections over oral MTX? I presume it is due to the severity of your arthritis symptoms.
How about increasing your Remicade to 6 week intervals? This was the approach when my arthritic symptoms were not being covered well with 8 week intervals.
Jan