This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
All are true regarding selective estrogen receptor down (SERD) Fulvestrant exept 
Select and explain. 
A. Used for treatment of advanced breast cancer, B. Is a selective estrogen antagonist, C. Is slower, sho acting and less safer than SERMS, D. Administered as once month i.m. dose
C: Is slower, sho acting and less safer than SERMS
Answer: C: Is slower, sho acting and less safer than SERMS 
Explanation: 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)