18. Women who are pregnant, breast-feeding, or women of child bearing potential not using estro-progestative oral or intra-uterine contraception or implants, or women using estro-progestative oral or intra-uterine contraception or implants but who consider stopping it during the planned duration of the study. A postmenopausal state is defined as no menses for 12 months without an alternative medical cause. (Contraception must be continued for one week following discontinuation of study drug).