title: [Plasma concentrations of toremifene citrate and N-desmethyltoremifene in postmenopausal patients with breast cancer--comparison of 120 mg of toremifene citrate administered once a day and divided into 3 separate doses (t.i.d.)].
abstract: To determine whether plasma concentrations of toremifene citrate after administration of 120 mg/day of toremifene citrate given in three separate dose (t.i.d.) were similar to those when toremifene citrate was administered in a single daily doses (40 mg x 3 tablets), we examined changes in plasma concentrations of toremifene citrate (TOR) and its metabolite, N-desmethyltoremifene (TOR-1). In both the t.i.d. administration group and the single-dose administration group, plasma TOR and TOR-1 concentrations reached a constant state within 2 weeks after administration was started. Under the constant state, plasma TOR concentrations were 1,493.3 +/- 120.3 ng/ml in the t.i.d. administration group and 1,348 +/- 341.0 ng/ml in the single-dose administration group. Plasma TOR-1 concentrations were 2,378.3 +/- 186.5 ng/ml in the t.i.d. administration group and 2,144 +/- 475.3 ng/ml in the single-dose administration group. In both groups, plasma TOR-1 concentrations were 2 or more times higher than plasma TOR concentrations. These results show there were no differences in plasma concentrations between administration of 120 mg/day of toremifene citrate in divided daily doses (t.i.d.) and in a single daily dose. The two administration methods appear to produce clinically similar actions.
authors.affiliation: Dept. of Oncology, Osaka University Medical School.
authors.forename: E
authors.initials: E
authors.lastname: Shiba
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Taguchi
authors.forename: F
authors.initials: F
authors.lastname: Tsukamoto
authors.forename: S
authors.initials: S
authors.lastname: Noguchi
mesh_terms: D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage* / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood / Q000188:drug therapy*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D020845:Selective Estrogen Receptor Modulators / Q000008:administration & dosage* / Q000097:blood*; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000097:blood; D017312:Toremifene / Q000008:administration & dosage* / Q000097:blood*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen; C062264:N-desmethyltoremifene; D017312:Toremifene