purchasing cialis online Provided herein are methods of treating a subject with a hormone dependent breast disorder or hormone dependent reproductive tract disorder, the method comprising a dosing the subject with a first composition comprising tamoxifen; b determining or having determined the subject s tamoxifen metabolites profile in a test sample obtained from the subject; c determining a reduced level of subject s plasma endoxifen based on the subject s tamoxifen metabolites profile to compared to a level of reference plasma endoxifen in a reference tamoxifen metabolites profile; and d administering an oral composition comprising endoxifen or a salt or polymorph thereof to the subject