The role of flavin-containing monooxygenase (FMO) in the metabolism of tamoxifen and other tertiary amines.

Article Details

Citation

Krueger SK, Vandyke JE, Williams DE, Hines RN

The role of flavin-containing monooxygenase (FMO) in the metabolism of tamoxifen and other tertiary amines.

Drug Metab Rev. 2006;38(1-2):139-47.

PubMed ID
16684653 [ View in PubMed
]
Abstract

Tamoxifen is utilized in breast cancer therapy and in chemoprevention. Tamoxifen may enhance risk for other neoplasias, especially endometrial cancer. The risk:benefit depends on the rate of metabolic activation versus detoxication. Cytochrome P450-dependent alpha-hydroxylation, followed by sulfonation, represents a metabolic activation pathway, producing products capable of covalent DNA adduction. In contrast, tamoxifen N-oxygenation represents a detoxication pathway, with the caveat that N-oxides can be reduced back to the parent amines. The N-oxygenation pathway will be the focus for this review. Dr. David Kupfer pioneered studies on cytochrome P450 and flavin-containing monooxygenase (FMO) tamoxifen metabolism. We collaborated with Dr. Kupfer's laboratory and recently determined that the low level of tamoxifen N-oxide production in human liver microsomes may be explained by the kinetics of FMO1 versus FMO3.

DrugBank Data that Cites this Article

Drug Enzymes
DrugEnzymeKindOrganismPharmacological ActionActions
TamoxifenDimethylaniline monooxygenase [N-oxide-forming] 1ProteinHumans
Unknown
Substrate
Details
TamoxifenDimethylaniline monooxygenase [N-oxide-forming] 3ProteinHumans
Unknown
Substrate
Details