Contraindicated in:
Use Cautiously in:
CV: DVT, edema.
Derm: hot flashes.
EENT: blurred vision.
F and E: hypercalcemia.
GI: nausea, vomiting.
GU: UTERINE MALIGNANCIES, vaginal bleeding.
Hemat: leukopenia, thrombocytopenia.
MS: bone pain.
Neuro: confusion, depression, headache, STROKE, weakness.
Resp: PE.
Misc: tumor flare.
Drug-Drug:
Metastatic Breast Cancer
Adjuvant Treatment of Breast Cancer
Prevention of Breast Cancer in High-Risk Women or Ductal Carcinoma in Situ
Absorption: Well absorbed after oral administration.
Distribution: Widely distributed to tissues.
Metabolism/Excretion: Primarily metabolized by the liver via the CYP3A isoenzyme into N-desmethyltamoxifen and via the CYP2D6 isoenzyme into 4-hydroxytamoxifen. Both of these metabolites are further metabolized into endoxifen (N-desmethyltamoxifen via CYP2D6 and 4-hydroxytamoxifen via CYP3A). Both endoxifen and 4-hydroxytamoxifen are 30- to 100-fold more potent than tamoxifen in suppressing estrogen-dependent cell proliferation. The CYP2D6 enzyme system exhibits genetic polymorphism (7% of population may be poor metabolizers and may have significantly ↓ endoxifen concentrations and ↓ effectiveness of tamoxifen). Slowly eliminated in the feces. Minimal amounts excreted in the urine.
Half-life: 7 days.
NDC Code*