4. Female subject of childbearing potential has been using an effective means of contraception for 1 week prior to the preliminary visit. She also has agreed to remain abstinent, or to use oral birth control pills or single-barrier contraception (partner using condom or subject using diaphragm, contraceptive sponge or IUD) beginning at the preliminary visit and continuing till the end of the study. Women who are postmenopausal or status post-hysterectomy or tubal ligation are exempt from this requirement. (Postmenopausal is defined as no menses for the previous 1 year. If cessation of menses is within 18 months, FSH must be documented as elevated into the postmenopausal range before entry).