How it is administered

Tofacitinib is taken by mouth (orally). It is available as immediate-release tablets (5 mg and 10 mg), extended-release tablets (11 mg and 22 mg), and as an oral solution (1 mg/mL). The tablets should be swallowed whole and can be taken with or without food. The oral solution is measured using a special syringe provided with the medication.

How it works

Tofacitinib is a Janus kinase (JAK) inhibitor. JAKs are enzymes inside cells that help transmit signals from certain cytokines and growth factors, which are important for the development and function of blood cells and the immune system. By blocking JAKs, tofacitinib interferes with the signaling pathways that lead to inflammation and immune cell activity.

This action helps reduce inflammation and immune system overactivity, which is why tofacitinib is used in autoimmune diseases. In blood cancers, especially those involving abnormal immune cell growth, JAK pathways can play a role, though tofacitinib is not specifically approved for T-Cell Prolymphocytic Leukemia. Its main effects are to lower certain immune cell counts and reduce inflammatory markers in the blood.

Who Should take it

Tofacitinib is approved for adults with moderately to severely active rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis who have not responded well to other treatments. It is also approved for children (2 years and older) with polyarticular course juvenile idiopathic arthritis who have not responded to other medications.

It is not specifically approved for T-Cell Prolymphocytic Leukemia or other blood cancers, but it may be used in clinical trials or off-label in certain cases under specialist care. Always follow your doctor’s advice about whether this medication is appropriate for your condition.

Who should not take it

Tofacitinib should not be started in people with very low white blood cell counts (lymphocytes <500 cells/mm³ or neutrophils <1000 cells/mm³) or low hemoglobin (<9 g/dL). It should not be used if you have an active serious infection, including tuberculosis or other severe infections.

Caution is needed in people with a history of chronic infections, liver problems, or those at higher risk for blood clots, heart disease, or certain cancers. It is not recommended for people with severe liver impairment. Pregnant or breastfeeding women should avoid this medication unless specifically advised by their doctor.

Commonly used with

Tofacitinib is sometimes used with other non-biologic disease-modifying antirheumatic drugs (DMARDs) such as methotrexate, especially in rheumatoid or psoriatic arthritis. It should not be used with other biologic DMARDs or potent immunosuppressants like azathioprine or cyclosporine due to increased risk of infections and side effects.

Commonly tested with

In clinical studies, tofacitinib has been tested both alone and in combination with other DMARDs such as methotrexate. It has also been compared to biologic agents like adalimumab in trials for autoimmune diseases. It is not commonly tested with strong immunosuppressants or other JAK inhibitors due to safety concerns.