title: A randomized, double-blind, placebo-controlled, parallel-group study to evaluate the efficacy and safety of the extended-release tramadol hydrochloride/acetaminophen fixed-dose combination tablet for the treatment of chronic low back pain.
abstract: BACKGROUND
  Chronic low back pain is a common condition that is often difficult to treat. The combination of tramadol hydrochloride and acetaminophen in an extended-release formulation has been shown to provide rapid and long-lasting analgesic effects resulting from the synergistic activity of these 2 active ingredients.
  
  
  OBJECTIVE
  The goal of this study was to evaluate the efficacy and safety of extended-release tramadol hydrochloride 75-mg/acetaminophen 650-mg fixed-dose combination tablets (TA-ER) for the treatment of chronic low back pain.
  
  
  METHODS
  This Phase III, double-blind, placebo-controlled, parallel-group study enrolled 245 patients with moderate to severe (≥4 cm on a 10-cm visual analog scale) chronic (≥3 months') low back pain insufficiently controlled by previous NSAIDs or cyclooxygenase-2-selective inhibitors and randomly assigned them to receive 4 weeks of either TA-ER or placebo. The primary efficacy end point was the percentage of patients with a pain intensity change rate ≥30% from baseline to final evaluation. Secondary end points included quality of life (Korean Short Form-36), functionality (Korean Oswestry Disability Index), and adverse events.
  
  
  RESULTS
  The percentage of patients with a pain intensity change rate ≥30% was significantly higher (P < 0.05) in the TA-ER group than in the placebo group for both the full analysis set and the per-protocol population. Pain relief success rate from baseline was significantly higher with TA-ER versus placebo at days 8 and 15 but not at the final visit. Patients in the TA-ER group had significant improvements versus placebo in role-physical, general health, and reported health transition domains of the Korean Short Form-36 and significantly higher functional improvements in the personal care section of the Korean Oswestry Disability Index. Patient assessment of overall pain control as "very good" was also significantly higher with TA-ER than with placebo. Adverse events were reported more frequently with TA-ER than with placebo; the most common adverse events reported were nausea, dizziness, constipation, and vomiting.
  
  
  CONCLUSIONS
  TA-ER was significantly more effective than placebo in providing pain relief, functional improvements, and improved quality of life. It exhibited a predictable safety profile in patients with chronic low back pain. ClinicalTrials.gov identifier: NCT01112267.
authors.affiliation: Department of Orthopedic Surgery, Seoul National University College of Medicine, SMG-SNU Boramae Medical Center, Seoul, Korea.
authors.forename: Jae Hyup
authors.initials: JH
authors.lastname: Lee
authors.forename: Chong-Suh
authors.initials: CS
authors.lastname: Lee
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage* / Q000009:adverse effects; D000328:Adult; D000368:Aged; D000700:Analgesics / Q000008:administration & dosage* / Q000009:adverse effects; D059350:Chronic Pain / Q000188:drug therapy*; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004338:Drug Combinations; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D013607:Tablets; D014147:Tramadol / Q000008:administration & dosage* / Q000009:adverse effects; D016896:Treatment Outcome
chemical_list: D000700:Analgesics; D003692:Delayed-Action Preparations; D004338:Drug Combinations; D013607:Tablets; D000082:Acetaminophen; D014147:Tramadol
keywords: adverse event; chronic low back pain; extended-release tramadol HCl/acetaminophen fixed-dose combination; functional improvement; pain relief