Effect of preoperative intravenous vs oral acetaminophen on postoperative opioid consumption in an enhanced recovery after surgery (ERAS) program in patients undergoing open gynecologic oncology surgery.

OBJECTIVE: Both intravenous (IV) and oral acetaminophen provide effective opioid-sparing analgesia after surgery when used as part of a multimodal preemptive pain management strategy. The purpose of this study was to compare postoperative opioid consumption in patients undergoing open gynecologic oncology surgery who received preoperative IV vs oral acetaminophen within an enhanced recovery after surgery (ERAS) program. METHODS: Retrospective data were collected on consecutive patients undergoing open gynecologic oncology surgery from May 1, 2016 to February 28, 2018 in patients receiving either 1 g IV or oral acetaminophen preoperatively. Patients were given a preoperative multimodal analgesia regimen including acetaminophen, celecoxib, pregabalin and tramadol. The primary outcomes were morphine equivalent daily doses (MEDD) on postoperative days (POD) 0 and 1. Secondary outcomes included highest patient-reported pain score in the post-anesthesia care unit (PACU) and intraoperative MEDD. Regression models adjusted by matched pairs were fit to estimate the average treatment effect of IV vs oral acetaminophen on MEDD. RESULTS: Of 353 patients, 178 (50.4%) received IV acetaminophen and 175 (49.6%) received oral acetaminophen. When balancing across the matched samples, there was no difference in postoperative MEDD for POD 0 between the IV and oral acetaminophen groups (Beta = -1.11; 95% CI: -4.83 to 2.60; p = 0.56). On POD 1, there was no difference between the IV and oral groups (Beta = 2.24; 95% CI: -2.76 to 7.25; p = 0.38). CONCLUSIONS: There was no difference in postoperative opioid consumption between patients receiving preoperative IV or oral acetaminophen within an ERAS program for patients undergoing open gynecologic oncology surgery.