JAK Kinase Inhibitors Print Page

What are JAK Kinase Inhibitors?

  • This is in a class of medications called disease modifying antirheumatic drugs (DMARDs)
  • DMARDs are a slow acting but effective treatment for rheumatoid arthritis and other form of inflammatory arthritis.

What is the typical dose for a JAK Kinase Inhibitor?

  • tofacinitib (Xeljanz) – 5 mg twice per day, or 11 mg once daily, given by mouth
  • baricitinib (Olumiant) – 2 mg once daily, given by mouth
  • upadacitinib (Rinvoq) – 15 mg once daily, given by mouth

How do JAK Kinase inhibitors work?

  • JAK Kinase inhibitors are a relatively new DMARD, first approved for use in Canada in 2014
  • They work by blocking the effect of an immune pathway called JAK-STAT.  By doing this, it can help decrease the body’s inflammatory response, thereby decreasing joint inflammation.
  • The benefits of these medications can be seen in patients as early as 2-4 weeks after starting it.
  • They appears to be equally effective to other new medications for rheumatoid arthritis called biologics.

If I start a JAK Kinase inhibitor, can I stop my other DMARDs?

  • Most rheumatologists will suggest you continue with at least methotrexate, assuming you have not had side effects, in addition to a JAK Kinase Inhibitor. Studies have shown it works significantly better when combined with methotrexate.
  • Keep in mind: In most instances, your rheumatologist has recommended you start a new medication because your inflammatory arthritis has not been well controlled. It is important to try to control your disease as best as possible first, which may mean continuing all DMARDs for some time, before trying to decrease them.

What are the possible side effects of JAK Kinase Inhibitors?

  • While generally well tolerated, they can cause:
    • Upset Stomach
    • Increased risk for serious infections
    • Lower blood counts
    • Raise cholesterol
    • Irritate the liver
    • Increased risk for blood clots

What can I do to decrease my risk of side effects?

  • Stop your JAK Kinase Inhibitor any time you have a fever. It is usually safe to resume it once you are better.
  • Fevers and other severe illness should not be ignored and discussed with your doctor.
  • Follow your rheumatologist’s instructions for monitoring bloodwork regularly.
  • Let your physician know if you have any changes in your medical history.

What should I do if I miss my dose?

  • If you miss your dose, do not take an extra dose, but just resume your normal routine.  As long as this does not happen regularly, you will likely not feel any ill effects.

How can I safely stop a JAK Kinase Inhibitor?

  • It is safe to just stop; you do not need to slowly reduce the dose. However, keep in mind, if you were gaining any benefit, it will usually take a few weeks to lose it.


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