* Tofacitinib (Xeljanz) has been approved to treat moderate-to-severe rheumatoid arthritis in adults who've had an inadequate response to or cannot tolerate methotrexate.
* The drug can produce serious, even life-threatening, infections. The most common serious infections reported include pneumonia, cellulitis, herpes zoster, and urinary tract infection. Tuberculosis and other opportunistic infections are also possible.
* Tofacitinib can decrease various cell counts, and blood counts need to be assessed carefully before and during therapy.
Diane S. Aschenbrenner is the course coordinator for undergraduate pharmacology at Johns Hopkins University School of Nursing in Baltimore, MD. She also coordinates Drug Watch: email@example.com.