6. A female patient of childbearing potential (premenopausal by medical history) must have a negative pregnancy test on Day 0 and be using an effective method of birth control (although no birth control method is 100% effective, the following are considered effective means of contraception: surgical sterilization, use of oral contraceptives, barrier contraception using either a condom or diaphragm with spermicidal gel, an intrauterine device, or contraceptive hormone implant or patch) from Screening for the duration of the study.