Newer progestogens.

OBJECTIVE To review the literature on the most recent progestogens to be developed, to provide clinical comparisons with older progestogens and to look at the potential of products not yet marketed. DATA SOURCES Searches of Medline and Popline together with requests for bibliographies from the Population Council, Wyeth-Ayerst Research and Schering Health Care. STUDY SELECTION Information from technical papers was used to ascertain the metabolic characteristics and receptor binding affinities of the compounds. Previous reviews were scrutinised in order to make comparisons with older compounds. Any available trials were examined to ascertain efficacy, bleeding patterns and tolerability, more weight being given to comparative trials. DISCUSSION Five progestogens have been developed in the last decade. They are all devoid of androgenic activity; some have antiandrogenic activity. Combined oral contraceptive (COC) pills containing dienogest and drospirenone are already marketed. Nomegestrol and nestorone have been extensively studied as subdermal implants. CONCLUSIONS Newer progestogens used in combination with oestrogen behave very similarly to existing products. Progestogen-only products using new progestogens have potential for significantly better tolerability due to their lack of androgenic activity.