XELJANZ/XELJANZ XR may cause serious side effects, including Hepatitis B or C activation infection in people who carry the virus in their blood. If you are a carrier of the Hepatitis B or C virus (viruses that affect the liver), the virus may become active while you use XELJANZ/XELJANZ XR. Your healthcare provider may do blood tests before you start treatment with XELJANZ/XELJANZ XR and while you are using XELJANZ/XELJANZ XR. Tell your healthcare provider if you have any of the following symptoms of a possible Hepatitis B or C infection: feel very tired, little or no appetite, clay-colored bowel movements, chills, muscle aches, skin rash, skin or eyes look yellow, vomiting, fevers, stomach discomfort, or dark urine.
These are not all the serious side effects of XELJANZ/XELJANZ XR.
To read more, see Important Safety Information. Patients should always ask their doctor for medical advice about adverse events.