TY - JOUR
T1 - Tamoxifen metabolites in patients on long-term adjuvant therapy for breast cancer
AU - Langan-Fahey, Susan M.
AU - Tormey, Douglass C.
AU - Craig Jordan, V.
PY - 1990
Y1 - 1990
N2 - Serum concentrations of tamoxifen, 4-OH-tamoxifen, N-desmethyltamoxifen, and metabolites E and Y were assayed to assess the variation of tamoxifen-metabolism during short-term and long-term endocrine treatment for breast cancer. Once steady-state was achieved, serum levels of tamoxifen and its metabolites in individual patients were stable in the short (10 weeks) and long term (over 7 years) (coefficient of variation [CV], 10-15%), but the variation between individuals (CV 50-70%) was high. Serum tamoxifen and N-desmethyltamoxifen levels were not correlated with indices of obesity. Thus this does not explain the large variation between individuals. In addition to the metabolites that were measured, 4-hydroxy-N-desmethyltamoxifen was tentatively identified in patients' serum. Overall, this study demonstrated that the metabolites of tamoxifen are stable (i.e. no metabolic tolerance) for up to 10 years of drug administration.
AB - Serum concentrations of tamoxifen, 4-OH-tamoxifen, N-desmethyltamoxifen, and metabolites E and Y were assayed to assess the variation of tamoxifen-metabolism during short-term and long-term endocrine treatment for breast cancer. Once steady-state was achieved, serum levels of tamoxifen and its metabolites in individual patients were stable in the short (10 weeks) and long term (over 7 years) (coefficient of variation [CV], 10-15%), but the variation between individuals (CV 50-70%) was high. Serum tamoxifen and N-desmethyltamoxifen levels were not correlated with indices of obesity. Thus this does not explain the large variation between individuals. In addition to the metabolites that were measured, 4-hydroxy-N-desmethyltamoxifen was tentatively identified in patients' serum. Overall, this study demonstrated that the metabolites of tamoxifen are stable (i.e. no metabolic tolerance) for up to 10 years of drug administration.
UR - http://www.scopus.com/inward/record.url?scp=0025251643&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025251643&partnerID=8YFLogxK
U2 - 10.1016/0277-5379(90)90191-U
DO - 10.1016/0277-5379(90)90191-U
M3 - Article
C2 - 2145931
AN - SCOPUS:0025251643
SN - 0277-5379
VL - 26
SP - 883
EP - 888
JO - European Journal of Cancer and Clinical Oncology
JF - European Journal of Cancer and Clinical Oncology
IS - 8
ER -