Tioguanine

Should be taken on an empty stomach (i.e. At least one hour before food or two hours after food).

Prior resistance to tioguanine or mercaptopurine. Pregnancy and lactation. Immunisation with live vaccines.

Patients with TPMT and NUDT15 deficiency (e.g. TPMT and NUDT15 intermediate, possible intermediate, and poor metabolisers); Lesch-Nyhan syndrome. Not recommended for maintenance therapy or long-term continuous treatment. Renal and hepatic impairment. Patient Counselling Avoid excessive exposure to sunlight, wear protective clothing and use sunscreen. Monitoring Parameters Consider TPMT genotypic or phenotypic tests, and NUDT15 genotypic tests to identify deficiency prior to treatment initiation. Monitor CBC with differential and platelet count frequently; LFTs weekly at the beginning of treatment and monthly thereafter (more frequently in patients with hepatic disease or concomitantly receiving other hepatotoxic drugs); serum uric acid. Monitor for signs and symptoms of hepatotoxicity, tumour lysis syndrome and myelosuppression. Monitor adherence.

Significant: Bone marrow suppression (e.g. leucopenia, thrombocytopenia, anaemia), hepatoxicity manifested as hepatic veno-occlusive disease/hepatic sinusoidal obstruction syndrome (e.g. hyperbilirubinaemia, hepatomegaly, weight gain caused by fluid retention and ascites), portal hypertension (e.g. splenomegaly, oesophageal varices), hepatoportal sclerosis, nodular regenerative hyperplasia, peliosis hepatitis, periportal fibrosis, elevated liver enzymes; secondary malignancies, tumour lysis syndrome, hyperuricaemia, photosensitivity. Blood and lymphatic system disorders: Pancytopenia. Gastrointestinal disorders: Stomatitis, nausea, vomiting, diarrhoea. Rarely, intestinal necrosis or perforation. Hepatobiliary disorders: Jaundice. Rarely, hepatic necrosis. Investigations: Increased blood alkaline phosphatase and gamma glutamyl transferase. Metabolism and nutrition disorders: Anorexia. Renal and urinary disorders: Hyperuricosuria, urate nephropathy.
Potentially Fatal: Infections and bleeding due to granulocytopenia and thrombocytopenia.

Increased risk of bone marrow suppression with other myelotoxic drugs or radiation therapy. May increase risk of TPMT deficiency with aminosalicylate derivatives (e.g. olsalazine, mesalazine, sulfasalazine). Increased risk of nodular regenerative hyperplasia, portal hypertension and oesophageal varices with busulfan.

Cytotoxic Chemotherapy

L01BB03 - tioguanine ; Belongs to the class of antimetabolites, purine analogues. Used in the treatment of cancer.