Figure 5.

Efficacy of tramadol ER in patients with osteoarthritis: mean change from baseline in Arthritis Pain Intensity VAS assessed through 12 weeks. Reprinted from Babul N, Noveck R, Chipman H, et al. 2004. Efficacy and safety of extended-release, once-daily tramadol in chronic pain: a randomized 12-week clinical trial in osteoarthritis of the knee. J Pain Symptom Management, 28:59–71. Copyright © 2004 with permission from Elsevier.

Abbreviations: ER, extended release; VAS, Visual Analogue Scale.