What is Xelianz
Xeljanz (tofacitinib) is a Disease Modifying Anti-Rheumatic Drug (DMARD) that suppresses the immune system to treat moderate to severe rheumatoid arthritis. Xeljanz is currently used to treat rheumatoid arthritis with and without the medication methotrexate. Xeljanz is also used to treat psoriatic arthritis and ulcerative colitis.
Xeljanz belongs to a class of medications known as Janus Kinase JAK) inhibitors. It is the first medication of this class to be approved for clinical trials and was first approved for use as a prescription medicine in 2012.
Who Should NOT Take Xeljanz
Patients should contact their doctor before intentionally missing a dose of Xeljanz. However, in the following situations, it would be advisable to stop taking the medicine and call a doctor:
Patients who are about to have surgery should discuss stopping Xeljanz with their doctor.
Some medications may not be safe to take with Xeljanz including ketoconazole, fluconazole, and rifampin. Patients should always discuss all of the medications that they are taking with their doctor.
Some medications may increase the risk of infection and should not be taken with Xeljanz, including biologics and other potent immunosuppressive medications such as cyclosporine or azathioprine.
How Xeljanz Works
One way that cells in the body communicate with each other is with special signalling proteins called cytokines. Cytokines are made and released by cells and drift around and until they encounter another cell and bind to a receptor on its surface.
When a cytokine binds to the surface of a cell, it passes its message to the cell’s nucleus (its “brain” or command centre) using a process called signal transduction. The nucleus responds to a signal by producing the appropriate protein or peptide that’s coded for in its DNA (this is called activation of transcription).
One of the important signal transduction pathways in the body uses an enzyme called Janus Kinase (JAK) and another molecule called Signal Transducer and Activation of Transcription (STAT) to send a signal to a cell’s nucleus.
The JAK-STAT pathway is important for sending signals related to bone marrow and immune system activation.
Xeljanz is a small molecule that enters a cell and binds to the ATP binding site on the enzyme Janus Kinase (JAK). In doing this, it prevents JAK from activating STAT. This blocks the process of sending a signal to the cell’s nucleus.
In rheumatoid arthritis, psoriatic arthritis, ulcerative colitis and many other autoimmune disorders, the immune system is not functioning correctly. It attacks the body’s own tissues the same way it attacks disease-causing germs.
By disrupting a key signal sending process related to immune system activation, Xeljanz interferes with the ability of immune system cells to talk with each other. When these cells can’t communicate as effectively, they have a hard time coordinating their attack on the body’s joints. The result is improvement in the symptoms of a patient’s arthritis.
Xeljanz is one of the few therapies for arthritis that is available as an oral tablet. The standard dose is either one 11 mg tablet taken once a day or a 5 mg tablet, taken twice every day.
Xeljanz does not work right away. It can take about 2 to 8 weeks before patients start feeling better, and it can take 3 to 6 months to feel the maximum effect of this medication. If the dose is changed, it can take 2-8 weeks to feel the effects.
The manufacturer of Xeljanz offers a support program to Canadian patients that are prescribed the medication:
Important Tests and Risks
The most common side effects of Xeljanz include include upper respiratory tract infections (common cold, sinus infections) and related symptoms.
Xeljanz might also cause headaches or diarrhea. Patients should tell their doctor if these effects are troublesome.
LESS SERIOUS side-effects include:
MORE SERIOUS side-effects include:
How to minimize the side-effects of Xeljanz:
When to Call a Doctor
Patients taking Xeljanz should call their doctor if they feel sick and want to stop, or if they are concerned about any side effects.
Other reasons to call a doctor while taking Xeljanz include: