Tofacitinib (Xeljanz)

Tofacitinib is the generic name of Xeljanz and Xeljanz XR, made by Pfizer. It belongs to a drug class called JAK (Janus kinase) inhibitors, which calm the immune system by blocking signaling enzymes. It is used for rheumatoid arthritis, psoriatic arthritis, ulcerative colitis, and some other inflammatory conditions.

Its safety history is why people search for it. FDA required Pfizer to run a large safety trial comparing Xeljanz with another class of arthritis drugs, TNF blockers. After reviewing the results, FDA concluded in 2021 that there is an increased risk of serious heart-related events such as heart attack or stroke, cancer, blood clots, and death with Xeljanz and Xeljanz XR. FDA required revisions to the Boxed Warning, its most prominent warning, for Xeljanz and two related JAK inhibitors, Olumiant (baricitinib) and Rinvoq (upadacitinib), and limited their approved uses to patients who had not responded to or could not tolerate TNF blockers.

In lawsuits, a stronger warning added years after a drug's launch is often a key piece of evidence. Plaintiffs in drug cases typically argue the company knew or should have known of a risk earlier and failed to warn doctors. A person considering a claim would generally need records showing they took the drug before the warning changed, and a diagnosed injury such as a blood clot in the lungs or legs, a heart attack, a stroke, or certain cancers.

Do not stop a prescribed drug without talking to your doctor. For how drug injury cases are grouped and handled, see what is MDL and class action vs. mass tort.