List of products in the National Drug Code with proprietary name . Tofacitinib is used to treat certain types of arthritis (such as psoriatic arthritis, rheumatoid arthritis, polyarticular course juvenile idiopathic arthritis-pcJIA). It helps to decrease pain/tenderness/swelling in the joints. Tofacitinib is also used to treat a certain bowel disease (ulcerative colitis). It helps to reduce symptoms of ulcerative colitis such as diarrhea, rectal bleeding, and stomach pain.