COMPARATIVE PHARMACOKINETICS OF DROLOXIFE NE AND TAMOXIFEN

In a comparative pharmakokinetic analysis between tamoxifen (T) and th e new antiestrogen droloxifene (D), 28 patients with metastatic breast cancer have been treated since 1985 with 40 mg per os daily of the an tiestrogens in a double-blind randomised study. During the first 3 tre atment months and following the end of treatment, blood samples were t aken at well-defined times in order to investigate routine laboratory parameters as well as serum concentrations of T and D and their metabo lites. Due to its completely different metabolism pathway, the pharmak okinetic data of droloxifene in serum show quick absorption, almost no accumulation and rapid elimination. This enables the substance to rea ct sooner with its target, resulting in shorter times to treatment eff ects compared with tamoxifen. Finally the therapeutic flexibility will be improved.