 You will return to the clinic at the end of Weeks 1, 2, 4, 6, 8, 10 and 12 for questionnaires about your pain levels, ability to sleep, constipation, other side effects, and quality-of-life. You will complete 6 questionnaires at the Weeks 1, 2, 6, 10, and 11 visit. You will complete 11 questionnaires at the Weeks 4, 8, and 12 visits. Each questionnaire will take 1-3 minutes to complete. The visit with the research nurse will last about 45 minutes to 1 hour. Your study drug supply will also be checked. You also will be asked about your overall health, non-health care questions, and activity level. At these visits, you will receive a new prescription for a 2-week supply of the study drug. 