title: The prevention of chronic postsurgical pain using gabapentin and pregabalin: a combined systematic review and meta-analysis.
abstract: BACKGROUND
  Many clinical trials have demonstrated the effectiveness of gabapentin and pregabalin administration in the perioperative period as an adjunct to reduce acute postoperative pain. However, very few clinical trials have examined the use of gabapentin and pregabalin for the prevention of chronic postsurgical pain (CPSP). We (1) systematically reviewed the published literature pertaining to the prevention of CPSP (≥ 2 months after surgery) after perioperative administration of gabapentin and pregabalin and (2) performed a meta-analysis using studies that report sufficient data. A search of electronic databases (Medline, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, IPA, and CINAHL) for relevant English-language trials to June 2011 was conducted.
  
  
  METHODS
  The following inclusion criteria for identified clinical trials were used for entry into the present systematic review: randomization; double-blind assessments of pain and analgesic use; report of pain using a reliable and valid measure; report of analgesic consumption; and an absence of design flaws, methodological problems or confounders that render interpretation of the results ambiguous. Trials that did not fit the definition of preventive analgesia and did not assess chronic pain at 2 or more months after surgery were excluded.
  
  
  RESULTS
  The database search yielded 474 citations. Eleven studies met the inclusion criteria. Of the 11 trials, 8 studied gabapentin, 4 of which (i.e., 50%) found that perioperative administration of gabapentin decreased the incidence of chronic pain more than 2 months after surgery. The 3 trials that used pregabalin demonstrated a significant reduction in the incidence of CPSP, and 2 of the 3 trials also found an improvement in postsurgical patient function. Eight studies were included in a meta-analysis, 6 of the gabapentin trials demonstrated a moderate-to-large reduction in the development of CPSP (pooled odds ratio [OR] 0.52; 95% confidence interval [CI], 0.27 to 0.98; P = 0.04), and the 2 pregabalin trials found a very large reduction in the development of CPSP (pooled OR 0.09; 95% CI, 0.02 to 0.79; P = 0.007).
  
  
  CONCLUSIONS
  The present review supports the view that perioperative administration of gabapentin and pregabalin are effective in reducing the incidence of CPSP. Better-designed and appropriately powered clinical trials are needed to confirm these early findings.
authors.affiliation: Department of Anesthesia and Pain Management, Toronto General Hospital, 200 Elizabeth Street, Eaton North 3 EB 317, Pain Research Unit, Toronto, ON M5G 2C4, Canada. hance.clarke@utoronto.ca
authors.forename: Hance
authors.initials: H
authors.lastname: Clarke
authors.forename: Robert P
authors.initials: RP
authors.lastname: Bonin
authors.forename: Beverley A
authors.initials: BA
authors.lastname: Orser
authors.forename: Marina
authors.initials: M
authors.lastname: Englesakis
authors.forename: Duminda N
authors.initials: DN
authors.lastname: Wijeysundera
authors.forename: Joel
authors.initials: J
authors.lastname: Katz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000588:Amines / Q000008:administration & dosage*; D000700:Analgesics / Q000008:administration & dosage*; D059350:Chronic Pain / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D019317:Evidence-Based Medicine; D005260:Female; D000077206:Gabapentin; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010147:Pain Measurement; D010149:Postoperative Pain / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D059035:Perioperative Period; D000069583:Pregabalin; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D000069583:Pregabalin; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin