Intravenous Acetaminophen Versus Placebo in Post-bariatric Surgery Multimodal Pain Management: a Meta-analysis of Randomized Controlled Trials



Pain management after bariatric surgery is challenging. Recent trials have been exploring the role of intravenous (IV) acetaminophen in multimodal analgesic therapy. This systematic review and meta-analysis assessed the effect of IV acetaminophen compared to placebo for pain management after bariatric surgery.


A comprehensive search of MEDLINE, Embase, CENTRAL, and PubMed databases were performed. Randomized controlled trials (RCTs) comparing IV acetaminophen to placebo as part of multimodal pain management after bariatric surgery in patients with obesity were included. Key outcomes were analyzed using random-effects meta-analysis, and the certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE).


Four RCTs including 349 patients met the inclusion criteria, of whom 175 were provided IV acetaminophen and 174 were provided placebo. Patients given IV acetaminophen demonstrated a lower postoperative pain score (mean difference (MD) − 0.66, 95% CI − 1.03 to − 0.28, P < 0.001) 24 h after surgery and lower postoperative opioid use (MD − 6.44, 95% CI − 9.26 to − 3.61, P < 0.001; I2 = 0%) in morphine equivalent doses (MED) within 24 h compared with the placebo group. There was no significant difference in length of stay between groups (MD − 0.26, 95% CI − 0.55 to 0.03, P = 0.08).


The use of IV acetaminophen after bariatric surgery is effective in reducing pain score after 24 h and postoperative opioid doses, but not length of stay. Provided the benefits of IV acetaminophen, its addition to postoperative care and enhanced recovery programs may be warranted.

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Correspondence to Dennis Hong.

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Lee, Y., Yu, J., Doumouras, A.G. et al. Intravenous Acetaminophen Versus Placebo in Post-bariatric Surgery Multimodal Pain Management: a Meta-analysis of Randomized Controlled Trials. OBES SURG 29, 1420–1428 (2019).

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  • Acetaminophen
  • Postoperative pain management
  • Multimodal analgesia
  • Meta-analysis