2015 Antineoplastics

III. Drugs that cause DNA strand breaks

Topoisomerase Inhibitors
(click here to review the difference between TopoI and TopoII)

  • CCS: S and G2 phases

  • ETOPOSIDE forms a complex with topoisomerase II and DNA that results in double-strand breaks - remains bound to the enzyme so that repair cannot occur

  • IRINOTECAN and TOPOTECAN are potent inhibitors of topoisomerase I - causes single-strand breaks
    • prodrugs (i.e., they must be activated)
    • IRINOTECAN is eliminated by liver metabolism, and excreted in the bile and feces (see side effects)
    • TOPOTECAN (and other "TECAN"s) are eliminated by a combination of metabolism and kidney excretion, making them better alternatives in some patients
Email: Dr. Janet Fitzakerley | ©2015 University of Minnesota Medical School Duluth | Last modified: 11-apr-15 9:39 AM