Effect of intraoperative or postoperative intravenous acetaminophen on postoperative pain scores and opioid requirements in abdominal and spinal surgery patients

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Department of Mathematical Sciences


Acetaminophen is a commonly used non-opioid analgesic with a well-established safety and tolerability profile. This retrospective study investigated the effects of intraoperative vs postoperative administration of intravenous (IV) acetaminophen on opioid consumption and pain scores in surgical patients. We included 147 patients who underwent abdominal or orthopedic spinal surgery who met all inclusion criteria; 41 patients received IV acetaminophen intraoperatively, 52 patients received it postoperatively and 54 control patients who did not receive IV acetaminophen. Patient outcomes were measured through 24-hour Visual Analog Scale (VAS) for pain scores, 24-hour opioid consumption, post-anesthesia care unit (PACU) pain scores, PACU and hospital length of stay and the time to first ambulation. The patients in the intraoperative IV acetaminophen group had a) significantly decreased 24-hour average pain scores (4.3±1.7) compared to the postoperative IV acetaminophen group (6.3±1.5) and to the control group (5.3±1.5) (p<0.05), b) decreased 24-hour opioid consumption (102±168) compared to the control group (189±153) (p<0.001), and c) had lower PACU initial pain scores (4±3.5) compared to the control group (6±4) (p<0.05). Also, the patients in the intraoperative IV acetaminophen group had reduced length of hospital stay (4.2±3.2) when compared with those in the control group (5.6±3.3) (p<0.05). Intraoperative IV acetaminophen significantly reduced the intraoperative opioid requirements compared to the controls (54±97 vs 119±149) (p<0.05). Intraoperative IV acetaminophen administration as an adjunct analgesic decreased postoperative opioid requirements and enhanced analgesia.

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International Journal of Clinical and Experimental Medicine