Estradiol valerate and dienogest: a novel four-phasic oral contraceptive pill effective for pregnancy prevention and treatment of heavy menstrual bleeding.

Estradiol valerate and dienogest have been combined to create a novel four-phasic oral contraceptive pill effective for both pregnancy prevention and treatment of heavy menstrual bleeding. This formulation represents the only oral contraceptive pill available in the USA containing an estrogen component that is biologically active as the endogenous estrogen 17β-estradiol. This medication was developed out of efforts to replace the most common estrogen in contraceptive pills, ethinyl estradiol, which is known to be a potent inducer of hepatic protein synthesis. Estradiol valerate has been available since the 1970s in oral and injectable forms indicated for the treatment of menopausal climacteric symptoms. Dienogest has been used in other oral contraceptive pills for over 10 years. Previous attempts to develop an oral contraceptive pill with natural estradiol or estradiol valerate were unsuccessful due to poor cycle control. A novel dynamic-dosing regimen was devised to improve the bleeding pattern. This medication has been shown in several clinical trials to have good contraceptive efficacy and cycle control. Recent studies have also demonstrated that this medication is effective for the treatment of heavy menstrual bleeding. However, compared with other oral contraceptive pills, this medication is associated with a higher frequency of absent withdrawal bleeding. Furthermore, the dynamic dosing regimen requires relatively complex instructions for users who miss pills.