What to Know About Xeljanz (Tofacitinib)

The First JAK Inhibitor for Rheumatoid Arthritis

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Xeljanz (tofacitinib citrate) is an oral Janus kinase (JAK) inhibitor—a type of disease-modifying anti-rheumatic drug (DMARD)—used to treat moderately to severely active rheumatoid arthritis (RA) in adults. Typically prescribed after unsuccessful treatment with methotrexate, Xeljanz relieves joint pain, inflammation, and stiffness by reducing immune system activity through a different therapeutic pathway than other DMARDs.

Xeljanz is available in both immediate- and extended-release formulations. There is no generic.


Xeljanz is approved to treat rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. It can be used alone (as monotherapy) or combined with methotrexate or other non-biologic DMARDs.

Approved by the Food and Drug Administration (FDA) in 2012, Xeljanz is considered a small-molecule medication, not a biologic drug. Biologics block pro-inflammatory cytokines from outside the cell while Xeljanz works from the inside.

Xeljanz inhibits the JAK pathway—a signaling pathway inside cells that plays a significant role in inflammation associated with rheumatoid arthritis. JAKs are intracellular enzymes that transmit signals that arise from cytokine or growth factor-receptor interactions on the cell membrane.

In clinical trials, Xeljanz alone or in combination with another DMARD was shown to significantly reduce the signs and symptoms of RA and improve the ability to perform typical daily activities.

Before Taking

Xeljanz is indicated in rheumatoid arthritis treatment after methotrexate has failed to bring the disease into remission. Prior to prescribing Xeljanz, your healthcare provider will go over your medical history, including your current RA symptoms and previous treatment regimens.

In addition, your healthcare provider will perform skin tests to check for tuberculosis and run blood tests to check your cholesterol levels, liver enzymes, and blood cell counts. Baseline levels will be recorded before you start therapy with Xeljanz so they can be referenced later.

Periodic laboratory tests are recommended throughout the duration of treatment because Xeljanz may cause changes to certain types of white blood cells, hemoglobin, liver enzymes, and lipids.

You may also need to update your vaccinations prior to treatment with Xeljanz, as live-virus vaccines must be avoided while taking the drug. These vaccines include:

Precautions and Contraindications

Your healthcare provider will go over the potential benefits and risks of this drug with you prior to prescribing the treatment. Xeljanz may pose more of a risk to people with certain conditions. Tell your healthcare provider if you are age 50 or older, a smoker or former smoker, or have or have ever had:

In addition, let your healthcare provider know if you live or have ever lived in areas where the fungal infection histoplasmosis is more common, such as the Ohio or Mississippi River valleys, parts of Central and South America, Africa, Asia, and Australia.

Adequate studies of Xeljanz in pregnant women have not been performed. Xeljanz should only be used during pregnancy if the benefit of the drug outweighs the potential risk to the fetus.


Regular Xeljanz is to be taken twice daily—5 milligrams (mg) per dose.

Xeljanz-XR, the extended-release version, comes as an 11-mg tablet that is taken once daily.

Xeljanz can be taken with or without food and should be swallowed whole. Do not chew, split, or crush it.

If you miss a dose, take it as soon as you remember unless it is almost time for the next dose. In that case, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one. Ask your healthcare provider or pharmacist if you have any questions.

Side Effects

The most common adverse effects associated with Xeljanz, which occurred during the first three months of use in clinical trials, were:

Tell your healthcare provider if these symptoms are severe or do not go away.

Xeljanz may increase your cholesterol levels. Your healthcare provider will monitor your cholesterol closely while you are taking this medication.


There are also some serious side effects associated with taking Xeljanz. If you experience any of the following, call your healthcare provider immediately or seek emergency medical treatment:

Warnings and Interactions 

Xeljanz carries a black box warning for serious and potentially deadly adverse events. These include:

  • Serious infections leading to hospitalization or death, such as tuberculosis, bacterial, invasive fungi, viral, and other opportunistic infections
  • Serious heart-related events, blood clots, and death
  • Lymphoma and other malignancies
  • Epstein-Barr virus–associated lymphoproliferative disorder

Xeljanz should not be taken alongside biologic drugs. These include:

Some medications should be used with caution when taking Xeljanz and may require your healthcare provider to alter your dosage or monitor you for side effects including liver damage. These include:

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6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  6. U.S. Centers for Disease Control and Prevention. Histoplasmosis.