NCI Drug Dictionary

The NCI Drug Dictionary contains technical definitions and synonyms for drugs/agents used to treat patients with cancer or conditions related to cancer. Each drug entry includes links to check for clinical trials listed in NCI's List of Cancer Clinical Trials.

The levorotatory form of norgestrel and synthetic progestogen with progestational and androgenic activity. Levonorgestrel binds to the progesterone receptor in the nucleus of target cells, thereby stimulating the resulting hormone-receptor complex, initiating transcription, and increasing the synthesis of certain proteins. This results in a suppression of luteinizing hormone (LH) activity and an inhibition of ovulation, as well as an alteration in the cervical mucus and endometrium. Check for active clinical trials using this agent. (NCI Thesaurus)

US brand name:Norplant
Plan B
Chemical structure:
  • (17Alpha)-13-ethyl-17-hydroxy-18,19-dinorpregn-4-en-20-yn-3-one
  • 13-Ethyl-17-hydroxy-18,19-dinor-17alpha-pregn-4-en-20-yn-3-one