<unk>  is a progestin used in hormonal contraceptives.<unk>  is a mixture of two stereoisomers, dextro-norgestrel (CAS# 797-64-8) and levo-norgestrel (CAS# 797-63-7).  Only levonorgestrel is biologically active.  Therefore, while some medications may contain dextronorgestrel, they are often labeled in terms of their levonorgestrel content only, ignoring the inert isomer.
Norgestrel
Levonorgestrel 
Gestodene
Etonogestrel
Etonorgestrel
Leuprolide
Proligeston
Clomiphene