One of the antimetabolite group of drugs (see ANTIMETABOLITES), which includes methotrexate, ?uorouracil and thioguanine. These drugs are incorporated into new nuclear material in the cell or combine irreversibly with vital cellular enzymes, preventing normal cellular metabolism and division. Mercaptopurine is used mainly for the maintenance treatment of acute LEUKAEMIA, though it is increasingly proving valuable in the treatment of CROHN’S DISEASE. As with all CYTOTOXIC drugs, dosage must be carefully controlled; in particular it must be reduced if used concurrently with allopurinol. Side-effects include gastrointestinal upsets (including ulceration), and bone-marrow depression.... mercaptopurine
(thioguanine) n. a drug that prevents the growth of cancer cells (see antimetabolite) and is used in the treatment of leukaemias. It commonly reduces the numbers of white blood cells and platelets. Other side-effects include nausea, vomiting, loss of appetite, and jaundice.
TIPSS (transjugular intrahepatic porto-systemic shunt) see portal hypertension.... tioguanine