Tofacitinib (also referred to by its brand name Xeljanz) is a Janus Kinase (JAK) inhibitor. It works differently to any of the other treatments that are currently available to treat psoriatic arthritis.

Cytokines are proteins that work in the immune system and play a key role in controlling cell growth and immune responses. It is thought that cytokines are over-active in people with psoriatic arthritis, leading to the overproduction of inflammation, which in turn causes the signs and symptoms of this condition. Cytokines rely on a family of enzymes known as Janus Kinase (JAK) enzymes, to help them distribute their messages.

Xeljanz stops the activity of JAK enzymes, meaning that the inflammatory cycle of psoriatic arthritis is disrupted. Xeljanz is a tablet that is taken twice a day. At the moment, it can only be prescribed to people who have tried other DMARDs, including certain biologic treatments, and found that these have not worked or have stopped working.


The information on this page is also available in our psoriatic arthritis - secondary care information sheet.

October 2018 (Review: December 2020)