Clinical pharmacology of tamoxifen in patients with breast cancer: correlation with clinical data.
Blood tamoxifen levels were determined for patients with metastatic breast cancer following initial and chronic dosing at twice daily 10 mg/m2 or a 20 mg/m2 single dose. Median time to response was six weeks. Blood tamoxifen levels at that time were ten-fold greater than those obtained after an initial single dose; however, steady-state values were not achieved until 16 weeks of chronic dosing. On a loading dose schedule of 40 mg/m2 twice daily for seven days and 20 mg/m2 daily thereafter, blood levels greater than or equal to 10 mg/m2 twice daily steady-state values were reached in one week. Levels drawn at peak and trough times suggest that tamoxifen may be given on a once-daily basis. Tamoxifen half-life was 9-12 hours after the initial dose and seven days after chronic dosing.
D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004341:Drug Evaluation; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D009362:Neoplasm Metastasis; D010865:Pilot Projects; D013629:Tamoxifen / Q000097:blood* / Q000627:therapeutic use
D013629:Tamoxifen