A semisynthetic analogue of camptothecin that inhibits topoisomerase I and used as a chemotherapeutic agent. It is a prodrug and is enzymically converted to the active metabolite SN-38, which is in turn inactivated by the enzyme UDP glucoronosyltransferase 1A1 (UGT1A1) by glucuronidation. People with variants of UGT1A1 called TA7 (see Gilbert's syndrome) have less enzyme in the liver and thus clear the drug more slowly; pharmacogenomic testing is therefore required to prevent excessive dosage. TN Camptosar.
Subjects: Clinical Pharmacology and Therapeutics.