Pfizer

Chemical Name: ETHYNODIOL (e-thye-no-DYE-ole) DIACETATE and ETHINYL ESTRADIOL (ETH-in-il ess-tra-DYE-ole)

Demulen contains two types of hormones, estrogens (ES-troh-jenz) and progestins (proh-JES-tins) and, when taken properly, prevents pregnancy. It works by stopping a woman's egg from fully developing each month. The egg can no longer accept a sperm and fertilization is prevented. Although oral contraceptives have other effects that help prevent a pregnancy from occurring, this is the main action.

SIDE EFFECTS that may go away during treatment include nausea, vomiting, bleeding between menstrual periods, breast tenderness, or weight change. If they continue or are bothersome, check with your doctor.