50 patients suffering from chronic low back pain were randomized to investigate the effect of acetaminophen and tramadol in achieving favorable outcomes of function, self-reported disability, and pain relief in patients, when compared to a placebo administered over 2 weeks. The evidence presented in this study suggested that the use of acetaminophen and tramadol did not produce significant improvements in functional capacity or self-reported disability when compared to placebo in chronic low back pain patients. Further analysis pertaining to responders observed improved functioning as a result of treatment with analgesics, and responders reported lower catastrophizing scores.