title: Systematic review and meta-analysis of efficacy, safety, and tolerability data from randomized controlled trials of drugs used to treat postherpetic neuralgia.
abstract: OBJECTIVE
  To conduct a systematic review of available data from reports of randomized controlled trials on the efficacy, safety, and tolerability of drugs used to treat postherpetic neuralgia (PHN), a common type of neuropathic pain.
  
  
  METHODS
  The MEDLINE (1950-June 30, 2009) and EMBASE (1974-June 30, 2009) databases were used to identify source studies, in conjunction with a review of reference citations from identified published reports.
  
  
  METHODS
  We selected all English-language reports of randomized placebo-controlled trials of the efficacy, tolerability, and safety of drugs (oral or transdermal) used for treatment in patients with PHN. Studies with treatment duration less than 4 weeks were excluded. From each identified trial, we extracted information on (1) placebo-corrected percentage reductions in pain intensity from randomization to end of active treatment; (2) relative risks of withdrawal due to lack of efficacy; (3) relative risks of various adverse events; and (4) relative risks of withdrawal due to adverse events.
  
  
  RESULTS
  Twelve reports of randomized controlled trials in patients with PHN were identified, involving 8 different agents (amitriptyline, capsaicin, divalproex sodium, gabapentin, morphine, nortriptyline, pregabalin, tramadol). Most studies were small, involving fewer than 200 patients. Pain intensity was reported to have been reduced significantly with all drugs (range: 13.8% [tramadol] to 42.4% [amitriptyline]); data were pooled using techniques of meta-analysis when information was available from more than 1 trial. No clinical trial reported a significant reduction in risk of withdrawal as a result of lack of efficacy. Analysis of adverse events was greatly limited by erratic and inconsistent reporting and wide variation in sample sizes.
  
  
  CONCLUSIONS
  While available literature establishes the efficacy of 8 drugs in treatment of PHN, it does not provide adequate guidance as to which agents are best to treat this condition, in part because of inadequate reporting of data on tolerability and safety.
authors.affiliation: Policy Analysis Inc., Brookline, MA, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Edelsberg
authors.forename: Claudia
authors.initials: C
authors.lastname: Lord
authors.forename: Gerry
authors.initials: G
authors.lastname: Oster
mesh_terms: D000700:Analgesics / Q000009:adverse effects* / Q000627:therapeutic use*; D006801:Humans; D051474:Neuralgia, Postherpetic / Q000188:drug therapy*; D017063:Outcome Assessment, Health Care; D016032:Randomized Controlled Trials as Topic; D012306:Risk; D018689:Sensory System Agents / Q000009:adverse effects* / Q000627:therapeutic use*
chemical_list: D000700:Analgesics; D018689:Sensory System Agents