Table 1. Competitive inhibitors of estrogen receptor alpha.

Antiestrogen	Class	Approved clinical indications
4-Hydroxytamoxifen (4-OHT)	SERM	• Adjuvant treatment for ER + breast cancers (Early Breast Cancer Trialists' Collaborative Group., 1998). • Metastatic Breast Cancer (Lipton, 1982). • Ductal Carcinoma in Situ (Allred et al., 2012). • Reduction in Breast Cancer Incidence in High Risk Women (Visvanathan, 2009).
Raloxifene (RAL)	SERM	• Osteoporosis in postmenopausal women (Messalli and Scaffa, 2010). • Reduction in Breast Cancer Incidence in High Risk Women(Cauley et al., 2001).
Fulvestrant (FULV)	SERD	• First-line therapy for metastatic breast cancer (Howell et al., 2004). • Postmenopausal women with progressive breast cancer following other antiestrogen therapy (Osborne et al., 2002; Howell et al., 2002).
Bazedoxifene (BZA)	SERM/SERD	• In combination with conjugated equine estrogens (DUAVEE) to prevent postmenopausal osteoporosis (Tikoo and Gupta, 2015).