Adverse effect profile comparison of pain regimens with and without intravenous acetaminophen in total hip and knee arthroplasty patients

BACKGROUND The use of adjunct, non-opioid agents is integral for pain control following total hip and knee arthroplasty. Literature comparing safety profiles of intravenous acetaminophen versus opioids is lacking. OBJECTIVE To determine whether there is a difference in frequency and type of adverse effects between intravenous acetaminophen-treated and non-intravenous acetaminophen-treated patients. Primary safety endpoints included any adverse effect noted in the electronic medical record post-surgically. Secondary endpoints included changes in laboratory values, vital signs, and pain scores. METHODS This is a retrospective, matched, cohort study with data collected from electronic medical records. Adverse effects were collected from progress notes, nursing notes, and post-operative notes. Mean pain score was measured by the 11-point visual analog scale over a 72-h period. RESULTS A total of 609 patients who underwent a total hip or knee replacement were included. In all, 406 patients were treated with intravenous acetaminophen, and 203 patients received medication management without intravenous acetaminophen. More patients treated with intravenous acetaminophen experienced an adverse effect compared to patients who did not receive intravenous acetaminophen (91.63% versus 84.73%; p = 0.012). Mean cumulative acetaminophen exposure was similar in the intravenous acetaminophen group (7704.89 ± 2558.6 versus 7260.1 ± 3016.09 mg; p = 0.07). Mean opioid use was similar in the intravenous acetaminophen group as compared to the non-intravenous acetaminophen group (209.61 ± 555.09 versus 163.89 ± 232.44 mg; p = 0.152). Significantly higher mean pain scores were found in the intravenous acetaminophen group during the 72-h post-surgery period as compared with non-intravenous acetaminophen-treated patients. CONCLUSION The increased utilization of intravenous acetaminophen in multimodal pain management did not result in an improved safety or tolerability profile or reduced opioid utilization in orthopedic patients.