Rituximab, commonly known as Rituxan and Mab Thera, is prescribed for non-Hodgkin’s lymphoma, chronic lymphocytic leukemia, to prevent transplant rejection and autoimmune disorders such as adult rheumatoid arthritis. Use of this drug has been associated with reactivation of hepatitis B virus in those testing positive for Hepatitis B and should not be used by those with active hepatitis B.