indication

ThioTEPA is used a as conditioning treatment prior to allogeneic or autologous haematopoietic progenitor cell transplantation (HPCT) in haematological diseases in adult and paediatric patients. Also, when high dose chemotherapy with HPCT support it is appropriate for the treatment of solid tumours in adult and paediatric patients.

pharmacology

The unstable nitrogen-carbon groups alkylate with DNA causing irrepairable DNA damage. They stop tumor growth by crosslinking guanine nucleobases in DNA double-helix strands, directly attacking DNA. This makes the strands unable to uncoil and separate. As this is necessary in DNA replication, the cells can no longer divide. These drugs act nonspecifically.

mechanism of action

The alkyl group is attached to the guanine base of DNA, at the number 7 nitrogen atom of the imidazole ring. They stop tumor growth by crosslinking guanine nucleobases in DNA double-helix strands, directly attacking DNA. This makes the strands unable to uncoil and separate. As this is necessary in DNA replication, the cells can no longer divide. These drugs act nonspecifically.

half life

1.5 to 4.1 hours

route of elimination

Urinary excretion of 14C-labeled thiotepa and metabolites in a 34-year old patient with metastatic carcinoma of the cecum who received a dose of 0.3 mg/kg intravenously was 63%.

drug interactions

Bupropion: Thiotepa, a strong CYP2B6 inhibitor, may decrease the metabolism and clearance of Bupropion, a CYP2B6 substrate. Consider alternate therapy or monitor for changes in the therapeutic and adverse effects of Bupropion if Thiotepa is initiated, discontinued or dose changed.

Cyclophosphamide: Thiotepa, a strong CYP2B6 inhibitor, may decrease the metabolism and clearance of Cyclophosphamide, a CYP2B6 substrate. Consider alternate therapy or monitor for changes in the therapeutic and adverse effects of Cyclophosphamide if Thiotepa is initiated, discontinued or dose changed.

Fosphenytoin: Possible increase in thiotepa levels

Irinotecan: Thiotepa, a strong CYP2B6 inhibitor, may decrease the metabolism and clearance of Irinotecan, a CYP2B6 substrate. Consider alternate therapy or monitor for changes in the therapeutic and adverse effects of Irinotecan if Thiotepa is initiated, discontinued or dose changed.

Ketamine: Thiotepa, a strong CYP2B6 inhibitor, may decrease the metabolism and clearance of Ketamine, a CYP2B6 substrate. Consider alternate therapy or monitor for changes in the therapeutic and adverse effects of Ketamine if Thiotepa is initiated, discontinued or dose changed.

Natalizumab: The immunosuppressant, Thiotepa, may increase the adverse effects of Natalizumab. Increased risk of Progressive Multifocal Leukoencephalopathy (PML) and other infections. Concurrent therapy should be avoided.

Phenytoin: Possible increase in thiotepa levels

Promethazine: Thiotepa, a strong CYP2B6 inhibitor, may decrease the metabolism and clearance of Promethazine, a CYP2B6 substrate. Consider alternate therapy or monitor for changes in the therapeutic and adverse effects of Promethazine if Thiotepa is initiated, discontinued or dose changed.

Selegiline: Thiotepa, a strong CYP2B6 inhibitor, may decrease the metabolism and clearance of Selegiline, a CYP2B6 substrate. Consider alternate therapy or monitor for changes in the therapeutic and adverse effects of Selegiline if Thiotepa is initiated, discontinued or dose changed.

Trastuzumab: Trastuzumab may increase the risk of neutropenia and anemia. Monitor closely for signs and symptoms of adverse events.