title: Systemic Metronidazole May Not Reduce Posthemorrhoidectomy Pain: A Meta-Analysis of Randomized Controlled Trials.
abstract: BACKGROUND
  Hemorrhoidectomy is associated with significant postoperative pain. Oral metronidazole has been recommended as an adjunct to improve posthemorrhoidectomy analgesia.
  
  
  OBJECTIVE
  This study aimed to evaluate the impact of oral metronidazole on patient-reported pain following hemorrhoidectomy.
  
  
  METHODS
  We conducted a systematic search in the MEDLINE, EMBASE, ISI Web of Science, and Cochrane Central Register of Controlled Trials databases.
  
  
  METHODS
  Randomized controlled trials examining adults who underwent surgical hemorrhoidectomy were included. Participants in an active intervention group received oral metronidazole postoperatively, and those in a control group received placebo or usual care. Postoperative pain was assessed for at least 3 days postoperatively.
  
  
  METHODS
  A random-effects model was used.
  
  
  METHODS
  The primary outcome was pain during the first 2 postoperative weeks, measured on a visual analogue scale. The secondary outcome was time to return to normal activities.
  
  
  RESULTS
  Patients who received oral metronidazole had significantly lower reported pain scores on postoperative day 1 (standardized mean difference, -0.87 ± 0.44; 95% CI, -1.73 to -0.015; p = 0.046; n = 4) and day 4 (standardized mean difference, -1.43 ± 0.71; 95% CI, -2.83 to -0.037; p = 0.044; n = 3). Metronidazole use was associated with a significantly shorter time to return to normal activities (standardized mean difference, -0.76 ± 0.34; 95% CI, -1.43 to -0.088, p = 0.027). The improvements disappeared in a sensitivity analysis excluding the largest trial with a high risk of bias, and no significance was observed during the remaining postoperative days.
  
  
  CONCLUSIONS
  The meta-analysis was limited by lack of double blinding, absence of a placebo, and unclear or high risk of bias in a proportion of the included trials.
  
  
  CONCLUSIONS
  Although a favorable adverse effect profile supports consideration of oral metronidazole to reduce posthemorrhoidectomy pain, pooled analysis reveals inconsistent results with no pain reduction on most postoperative days. The current recommendation for routine prescription of oral metronidazole should be reevaluated in the absence of additional well-designed trials.
authors.affiliation: 1 Department of Surgery, Western University, London Health Sciences Centre, London, Canada 2 Department of Physical Medicine & Rehabilitation, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
authors.forename: Kerollos Nashat
authors.initials: KN
authors.lastname: Wanis
authors.forename: Heather M
authors.initials: HM
authors.lastname: Emmerton-Coughlin
authors.forename: Shaun
authors.initials: S
authors.lastname: Coughlin
authors.forename: Norine
authors.initials: N
authors.lastname: Foley
authors.forename: Christopher
authors.initials: C
authors.lastname: Vinden
mesh_terms: D000284:Administration, Oral; D000700:Analgesics / Q000627:therapeutic use; D000890:Anti-Infective Agents / Q000627:therapeutic use*; D061865:Hemorrhoidectomy; D006484:Hemorrhoids / Q000601:surgery*; D006801:Humans; D008795:Metronidazole / Q000627:therapeutic use*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic; D020127:Recovery of Function; D013997:Time Factors
chemical_list: D000700:Analgesics; D000890:Anti-Infective Agents; D008795:Metronidazole