- Women of childbearing potential and females that are pre-menses must be willing to practice effective contraception for the duration of the study. (Effective contraception is defined as stabilized on oral contraceptive for at least 3 months, IUD, condom with spermicidal, diaphragm with spermicidal, implant, Nuvaring, injection, transdermal patch or abstinence.) Females on birth control pills must have taken the same type pill for at least three months prior to entering the study and must not change type during the study. Those who have used birth control pills in the past must have discontinued usage at least three months prior to the start of the study. Women who use birth control for acne control only should be excluded.