Duloxetine Versus Placebo in Chronic Low Back Pain

Inclusion Criteria: * Male/Female outpatients 18 years of age with chronic low back pain * Females of child bearing potential must test negative on a pregnancy test at visit 1. Exclusion Criteria: * Have a serious or unstable diseases of the heart or blood vessels, liver, kidney, lungs, or blood-related illness * Problems with decreased blood flow to arms and legs (peripheral vascular disease), or other medical conditions * Psychiatric conditions that, in the opinion of the investigator, would affect your participation or be likely to lead to hospitalization during the course of the study * Have acute liver injury (such as hepatitis) or severe cirrhosis * Have had previous exposure to duloxetine * Have a body mass index (BMI) over 40 * Have a major depressive disorder * Require daily narcotics * Have suicidal risk * Have a presence of any factors/conditions, medical or other, that in the judgment of the investigator may interfere with performance of study outcome measures