- Female subjects of childbearing potential must be using a medically acceptable form of birth control for at least 1 month prior to screening (3 months on oral contraceptives), e.g., oral or patch contraceptives, intrauterine device, injectable contraceptive (e.g. Depo-Provera), or a double barrier and have a negative pregnancy test at Screening and prior to study drug administration on Day 0 of Dosing Periods 1 and 2. Female subjects of non-childbearing potential must be amenorrheic for at least two years or had a hysterectomy and/or bilateral oophorectomy;