title: Gabapentin for chronic neuropathic pain and fibromyalgia in adults.
abstract: BACKGROUND
  This review updates parts of two earlier Cochrane reviews investigating effects of gabapentin in chronic neuropathic pain (pain due to nerve damage). Antiepileptic drugs are used to manage pain, predominantly for chronic neuropathic pain, especially when the pain is lancinating or burning.
  
  
  OBJECTIVE
  To evaluate the analgesic effectiveness and adverse effects of gabapentin for chronic neuropathic pain management.
  
  
  METHODS
  We identified randomised trials of gabapentin in acute, chronic or cancer pain from MEDLINE, EMBASE, and CENTRAL. We obtained clinical trial reports and synopses of published and unpublished studies from Internet sources. The date of the most recent search was January 2011.
  
  
  METHODS
  Randomised, double-blind studies reporting the analgesic and adverse effects of gabapentin in neuropathic pain with assessment of pain intensity and/or pain relief, using validated scales. Participants were adults aged 18 and over.
  
  
  METHODS
  Two review authors independently extracted data. We calculated numbers needed to treat to benefit (NNTs), concentrating on IMMPACT (Initiative on Methods, Measurement and Pain Assessment in Clinical Trials) definitions of at least moderate and substantial benefit, and to harm (NNH) for adverse effects and withdrawal. Meta-analysis was undertaken using a fixed-effect model.
  
  
  RESULTS
  Twenty-nine studies (3571 participants), studied gabapentin at daily doses of 1200 mg or more in 12 chronic pain conditions; 78% of participants were in studies of postherpetic neuralgia, painful diabetic neuropathy or mixed neuropathic pain. Using the IMMPACT definition of at least moderate benefit, gabapentin was superior to placebo in 14 studies with 2831 participants, 43% improving with gabapentin and 26% with placebo; the NNT was 5.8 (4.8 to 7.2). Using the IMMPACT definition of substantial benefit, gabapentin was superior to placebo in 13 studies with 2627 participants, 31% improving with gabapentin and 17% with placebo; the NNT was 6.8 (5.6 to 8.7). These estimates of efficacy are more conservative than those reported in a previous review. Data from few studies and participants were available for other painful conditions.Adverse events occurred significantly more often with gabapentin. Persons taking gabapentin can expect to have at least one adverse event (66%), withdraw because of an adverse event (12%), suffer dizziness (21%), somnolence (16%), peripheral oedema (8%), and gait disturbance (9%). Serious adverse events (4%) were no more common than with placebo.There were insufficient data for comparisons with other active treatments.
  
  
  CONCLUSIONS
  Gabapentin provides pain relief of a high level in about a third of people who take if for painful neuropathic pain. Adverse events are frequent, but mostly tolerable. More conservative estimates of efficacy resulted from using better definitions of efficacy outcome at higher, clinically important, levels, combined with a considerable increase in the numbers of studies and participants available for analysis.
authors.affiliation: Pain Research and Nuffield Department of Clinical Neurosciences (Nuffield Division of Anaesthetics), University of Oxford, Pain Research Unit, Churchill Hospital, Oxford, Oxfordshire, UK, OX3 7LJ.
authors.forename: R Andrew
authors.initials: RA
authors.lastname: Moore
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Wiffen
authors.forename: Sheena
authors.initials: S
authors.lastname: Derry
authors.forename: Henry J
authors.initials: HJ
authors.lastname: McQuay
mesh_terms: D000588:Amines / Q000009:adverse effects / Q000627:therapeutic use*; D000700:Analgesics / Q000009:adverse effects / Q000627:therapeutic use*; D002908:Chronic Disease; D003509:Cyclohexanecarboxylic Acids / Q000009:adverse effects / Q000627:therapeutic use*; D005356:Fibromyalgia / Q000188:drug therapy*; D000077206:Gabapentin; D006801:Humans; D009437:Neuralgia / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic; D005680:gamma-Aminobutyric Acid / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin