- Women of childbearing potential unwilling to use a medically approved and highly effective form of birth control while on study drug and for 2 weeks after last dose. Acceptable forms of birth control include an intrauterine device (IUD), oral contraceptives, condoms, abstinence, injectable contraceptive, or any other highly effective means of birth control. (A highly effective method of birth control is defined as those which result in a low failure rate [i.e. less than 1 percent per year] when used consistently and correctly.) Emergency contraceptive treatment and coitus interruptus are not considered effective forms of contraception.