- Females of childbearing potential are required to simultaneously use 2 effective contraceptive methods, 1 of which must be a barrier (condoms, diaphragm or cervical cap) with spermicide. Non-vasectomized men must be willing to abstain from sexual intercourse or willing to use a condom in addition to having their female partner use another form of contraception, if the woman could become pregnant from the time of the first dose of study medication until completion of follow up procedures