Mercaptopurine is a type of chemotherapy medicine called a nucleoside metabolic inhibitor. It works by interfering with the growth of cancer cells, especially those that multiply quickly, like the abnormal lymphocytes in acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma.

Inside the body, mercaptopurine is converted into active compounds called thioguanine nucleotides (TGNs). These compounds get incorporated into the DNA and RNA of cells, which disrupts their normal function and leads to cell-cycle arrest and cell death. Mercaptopurine also blocks the production of new purines, which are building blocks needed for making DNA and RNA. By stopping these processes, mercaptopurine helps to control the growth of cancer cells.

Because it targets rapidly dividing cells, mercaptopurine can also affect healthy cells that divide quickly, such as those in the bone marrow, which is why monitoring is important during treatment.

mercaptopurine

Common brand names

Approved use in