...swelling and significantly improve physical function. xeljanz xr can lower your ability to fight infections, including tuberculosis. serious, sometimes fatal infections and cancers, including lymphoma, have happened. as have tears in the stomach or intestines, serious allergic reactions, low blood cell counts, higher liver tests and cholesterol levels. don't start xeljanz xr if you have an infection. your doctor should perform blood tests before and while taking xeljanz xr, and monitor certain liver tests. tell your doctor if you've been somewhere fungal infections are common and if you hav...