- Women of childbearing potential must be using a medically accepted method of contraception (i.e. oral contraceptives, intrauterine devices) to avoid pregnancy during the 2 months preceding the start of study treatment, throughout the study period and for up to 3 months after the last dose of study treatment in such a manner that the risk of pregnancy is minimised. Women of childbearing potential must have a negative serum or urine pregnancy test within 72 hours prior to the start of study treatment.