<prompt> All are true regarding selective estrogen receptor down SERD Fulvestrant exeptUsed for treatment of advanced breast cancerIs a selective estrogen antagonistIs slower, sho acting and less safer than SERMSAdministered as once month i.m. dose  <response>: Fulvestrant is more efficient than tamoxifen,used in the treatment of metastatic ER positive breast cancer. It is a selective estrogen antagonist and is administered as 250mg monthly i.m Injections. Ref.Essentials of medical pharmacology TD Tripathi 7th edition page no 313 