What they are probably talking about is methotrexate which is an antimetabolite and antifolate drug used in treatment of cancer and autoimmune diseases. It acts by inhibiting the metabolism of folic acid. Lower doses of methotrexate have been shown to be very effective for the management of rheumatoid arthritis, Crohn's disease, and psoriasis. See all information at   http://en.wikipedia.org/wiki/Methotrexate   I was on it for a couple of years but I was 38. I don't know much about rh in kids. Hope this helps. Also I am almost completely med free after changing my diet 6 months ago to no gluten, wheat etc. at the advise of my rheumatologist.