title: Preventive Acetaminophen Reduces Postoperative Opioid Consumption, Vomiting, and Pain Scores After Surgery: Systematic Review and Meta-Analysis.
abstract: OBJECTIVE
  Preventive analgesia has been proposed as a potential strategy to reduce postoperative pain. However, there is currently no review that focuses on acetaminophen for preventive analgesia.
  
  
  METHODS
  We conducted a search of MEDLINE, EMBASE, Cinahl, AMED, and CENTRAL databases identifying randomized controlled trials that compared preventive acetaminophen with postincision acetaminophen.
  
  
  RESULTS
  Seven studies with 544 participants were included. Overall, the studies showed a reduction in 24-hour opioid consumption (standardized mean difference [SMD] of -0.52; 95% confidence interval [95% CI], -0.98 to -0.06), lower pain scores at 1 hour (MD, -0.50; 95% CI, -0.98 to -0.02) and 2 hours (MD, -0.34; 95% CI, -0.67 to -0.01), and a lower incidence of postoperative vomiting (risk ratio, 0.50; 95% CI, 0.31-0.83) in the preventive acetaminophen group. Current studies are limited by a potential risk of bias.
  
  
  CONCLUSIONS
  To our knowledge, this is the first review to describe a potential preventive effect of acetaminophen. However, well-conducted randomized controlled trials are necessary to substantiate the conclusions of this review.
authors.affiliation: From the Division of Medical Sciences and Graduate Entry Medicine, University of Nottingham, Derby, United Kingdom.
authors.forename: Brett
authors.initials: B
authors.lastname: Doleman
authors.forename: David
authors.initials: D
authors.lastname: Read
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Lund
authors.forename: John P
authors.initials: JP
authors.lastname: Williams
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage*; D000701:Analgesics, Opioid / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods; D010149:Postoperative Pain / Q000175:diagnosis / Q000517:prevention & control*; D020250:Postoperative Nausea and Vomiting / Q000175:diagnosis / Q000517:prevention & control*; D065129:Pre-Exposure Prophylaxis / Q000379:methods*
chemical_list: D000701:Analgesics, Opioid; D000082:Acetaminophen