A preliminary examination of the comparative efficacy of intravenous vs oral acetaminophen in the treatment of perioperative pain

Abstract

Objective. The management of postoperative pain is a major health care issue. While the cost of intravenous acetaminophen (IVA) is significantly greater than its oral acetaminophen (OA) counterpart, less is known regarding comparative effectiveness of these routes. The purpose of this study was to determine whether perioperative IVA is equivalent in reducing postoperative pain compared with perioperative OA for laparoscopic cholecystectomy (LapChole). Design. Double-blinded, prospective, randomized placebo-controlled trial. Setting. Womack Army Medical Center, Fort Bragg, North Carolina. Subjects. Adults (age > 18 years) active duty military, veterans, and beneficiaries receiving a laparoscopic cholecystectomy. Methods. This study was conducted at Womack Army Medical Center (WAMC), Fort Bragg, North Carolina, between January 2013 and June 2015. Sixty-seven subjects with symptomatic cholelithiasis were randomly assigned to receive two doses (1,000mg each) of either IVA or OA. A numerical rating scale (NRS) score of pain was obtained preoperatively and every six hours for 24 hours postoperation. The primary objective was to assess whether treatment groups had significantly different 24-hour postoperative sum of pain intensity differences (SPID24) using an analysis of covariance test. Results. Sixty subjects completed the study and were included in the analysis. Treatment groups did not differ in SPID24, even when controlling for age, gender, and preoperative pain levels (F(1,55) 5 0.39, P 5 0.54, partial η2 5 0.007), nor did 24-hour opioid consumption when controlling for age, gender, and operation time (F(1, 46) 5 0.47, P 5 0.50, partial η2 5 0.01). Furthermore, treatment groups were equally as likely to report average postoperative NRS scores of 4 or higher (β50.24, Exp(B) 5 1.28, P 5 0.68). Conclusions. The results show no evidence of differences between IVA or OA in pain or opioid consumption among a sample of patients undergoing LapChole. Due to low sample size, these descriptive findings warrant larger studies, which may have a significant economic impact.