title: Systematic review and meta-analysis of opioid antagonists for smoking cessation.
abstract: OBJECTIVE
  This meta-analysis sought to evaluate the efficacy of opioid antagonists in promoting long-term smoking cessation. Post-treatment abstinence was examined as a secondary outcome and effects on withdrawal symptoms, craving and reduced consumption were also explored.
  
  
  METHODS
  The search strategy for this meta-analysis included clinical trials (published and unpublished data) in the Cochrane Tobacco Addiction Group Specialized Register and MEDLINE.
  
  
  METHODS
  Adult smokers.
  
  
  METHODS
  We included randomised trials comparing opioid antagonists to placebo or an alternative therapy for smoking cessation and reported data on abstinence for a minimum of 6 months.
  
  
  METHODS
  Outcomes included smoking abstinence at long-term follow-up (primary); abstinence at end of treatment (secondary); and effects on withdrawal, craving and smoking consumption (exploratory).
  
  
  RESULTS
  8 trials with a total of 1213 participants were included. Half the trials examined the benefit of adding naltrexone versus placebo to nicotine replacement therapy (NRT). There was no significant difference between naltrexone and placebo alone (relative risk (RR) 1.00; 95% CI 0.66 to 1.51) or as an adjunct to NRT (RR 0.95; 95% CI 0.70 to 1.30), with an overall pooled estimate of RR 0.97; 95% CI 0.76 to 1.24. Findings for naltrexone effects on withdrawal, craving and reduced smoking were equivocal.
  
  
  CONCLUSIONS
  The findings indicate no beneficial effect of naltrexone alone or as an adjunct to NRT on short-term or long-term smoking abstinence. While further trials may narrow the confidence limits, they are unlikely to appreciably alter the conclusion.
authors.affiliation: Center for Education in Family & Community Medicine, Stanford University, Stanford, California, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: David
authors.forename: Isabella M
authors.initials: IM
authors.lastname: Chu
authors.forename: Tim
authors.initials: T
authors.lastname: Lancaster
authors.forename: Lindsay F
authors.initials: LF
authors.lastname: Stead
authors.forename: A Eden
authors.initials: AE
authors.lastname: Evins
authors.forename: Judith J
authors.initials: JJ
authors.lastname: Prochaska
mesh_terms: D000328:Adult; D006801:Humans; D009271:Naltrexone / Q000627:therapeutic use*; D009292:Narcotic Antagonists / Q000627:therapeutic use*; D012907:Smoking / Q000188:drug therapy*; D016540:Smoking Cessation; D061485:Tobacco Use Cessation Devices
chemical_list: D009292:Narcotic Antagonists; D009271:Naltrexone
keywords: naltrexone; opioid antagonists; smoking abstinence; smoking cessation; tobacco