- If female, are surgically sterile, two years postmenopausal, or if of child-bearing potential, must be using a medically acceptable method of birth control and agree to continue use of this method for the duration of the study. Acceptable methods include a barrier method with spermicide, oral contraceptives (normal doses are acceptable; low dose oral contraceptives or contraceptive implants must be used with a barrier method), intrauterine device (IUD), or abstinence. Have a negative pregnancy test.