title: Long-term tolerability of tramadol LP, a new once-daily formulation, in patients with osteoarthritis or low back pain.
abstract: BACKGROUND
  Tramadol hydrochloride is a centrally acting analgesic, which possesses opioid agonist properties and activates monoaminergic spinal inhibition of pain. An oral, once a day, sustained release formulation of tramadol is thought to be advantageous compared with immediate release preparations as it prevents plasma peaks associated with increased side-effects of the drug. It may also improve compliance. The purpose of the study was to assess the long-term safety of a new sustained-release formulation of tramadol (tramadol LP) in patients with knee or hip osteoarthritis and in patients with refractory low back pain.
  
  
  METHODS
  The design was a phase III, open, multicentre, international, tolerability study with tramadol LP at a dose titrated by the patient between 100 and 400 mg once daily, according to the intensity of pain. The treatment was administered for a continuous period of 4 weeks followed by an intermittent intake of 5 months in 204 patients. The safety criteria for evaluation were recording of adverse events, laboratory tests, electrocardiogram, radiography, global tolerability assessed by the patient and the investigators.
  
  
  RESULTS
  Long-term use of tramadol LP was reasonably well tolerated. Most of the reported adverse events were expected and occurred within the first month of treatment. Roughly half of the patients (49%) reported adverse events, of which 66% were related to treatment. Gastrointestinal events (nausea and vomiting) were the most frequent. Serious adverse events were reported in 6.4% of patients, from which only two cases were related to treatment. There was no sign of tolerance development and the percentage of patients presenting withdrawal symptoms after the end of treatment was low (6%).
  
  
  CONCLUSIONS
  Long-term treatment with tramadol LP once daily is generally safe in patients with osteoarthritis or refractory low back pain.
authors.affiliation: Laboratoire de Physiologie et de Pharmacologie, Institut de Pharmacie, Unversité Libre de Bruxelles, Brussels, Belgium. hugues.malonne@ulb.ac.be
authors.forename: H
authors.initials: H
authors.lastname: Malonne
authors.forename: M
authors.initials: M
authors.lastname: Coffiner
authors.forename: D
authors.initials: D
authors.lastname: Fontaine
authors.forename: B
authors.initials: B
authors.lastname: Sonet
authors.forename: A
authors.initials: A
authors.lastname: Sereno
authors.forename: A
authors.initials: A
authors.lastname: Peretz
authors.forename: F
authors.initials: F
authors.lastname: Vanderbist
mesh_terms: D000082:Acetaminophen / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000188:drug therapy*; D008297:Male; D009325:Nausea / Q000139:chemically induced / Q000453:epidemiology; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000188:drug therapy*; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D010148:Intractable Pain / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology; D017060:Patient Satisfaction; D011859:Radiography; D014147:Tramadol / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome; D014839:Vomiting / Q000139:chemically induced / Q000453:epidemiology
chemical_list: D003692:Delayed-Action Preparations; D000082:Acetaminophen; D014147:Tramadol