Tapentadol treatment results in long-term pain relief in patients with chronic low back pain and associates with reduced segmental sensitization

Introduction:Chronic low back pain (CLBP) is one of the most common chronic pain conditions in pain practice.Objectives:In the current study, we describe phenotypes of patients with CLBP based on the status of their endogenous pain modulatory system.Methods:Conditioned pain modulation (a measure of central pain inhibition), temporal summation (TS, a measure of pain facilitation), and offset analgesia (a measure of temporal filtering of nociception) were evaluated in 53 patients with CLBP at painful and nonpainful sites. Next, in a double-blind, randomized, placebo-controlled trial, 40 patients with defective conditioned pain modulation responses received treatment with tapentadol prolonged-release or placebo for 3 months.Results:The majority of patients (87%) demonstrated loss of central pain inhibition combined with segmentally increased TS and reduced offset analgesia at the lower back region. During treatment, tapentadol reduced pain intensity more than placebo (tapentadol -19.5 2.1 mm versus placebo -7.1 +/- 1.8 mm, P = 0.025). Furthermore, tapentadol significantly decreased pain facilitation by reduction of TS responses at the lower back (tapentadol -0.94 +/- 1.9 versus placebo 0.01 +/- 1.5, P = 0.020), which correlated with pain reduction (P < 0.001).Conclusion:Patients with CLBP demonstrated different phenotypes of endogenous pain modulation. In patients with reduced conditioned pain modulation, tapentadol produced long-term pain relief that coincided with reduction of signs of pain facilitation. These data indicate that the endogenous pain system may be used as a biomarker in the pharmacological treatment of CLBP, enabling an individualized, mechanism-based treatment approach.Perioperative Medicine: Efficacy, Safety and Outcome (Anesthesiology/Intensive Care