- Females of childbearing potential must be using an acceptable method of contraception, have a negative serum pregnancy test at screening, and a negative urine pregnancy test at baseline. Acceptable methods of contraception include oral, intrauterine, implantable, injectable contraceptives, hormonal patch, double barrier methods or condoms impregnated with spermicide. After screening, patients using oral contraceptive methods of contraception must agree to add an additional method until 30 days following the last dose of study medication. Women on oral contraceptives must have been using them for at least one month prior to screening;