- Female subjects of child-bearing potential must have a negative serum pregnancy test within seven days of the first dose and agree to use dual methods of contraception during and for 3 months following last dose of drug. Post menopausal females (> 45 years old and without menses for > 1 year) and surgically sterilized females are exempt from a pregnancy test. Male subjects must use an effective barrier method of contraception during study and for 3 months following the last dose if sexually active with a female of child-bearing potential.