Purinethol (Mercaptopurine) This medication is used with other drugs to treat a certain type of cancer (acute lymphocytic leukemia). It is a chemotherapy drug that works by slowing or stopping the growth of cancer cells.
Mercaptopurine is used to treat acute lymphoblastic or lymphocytic leukemia. Mercaptopurine is sometimes given with other cancer medications. Mercaptopurine may also be used for purposes not listed in this medication guide.