have a serious infection or an infection that does not go away or keeps coming back (chronic). Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Your healthcare provider will watch you closely while you are receiving TZIELD and after your infusion for signs of a reaction. Your healthcare provider will watch you closely while you are receiving TZIELD and after your infusion for signs of a reaction. For more information, ask your healthcare provider or pharmacist.