Tehran University of Medical Sciences Nursing Practice Today 2383-1154 7 2 2020 04 01 131 139 Sajad Yarahmadi Department of Critical Care Nursing, Faculty of Nursing and Midwifery, Lorestan University of Medical Sciences, Khorramabad, Iran AND Social Determinants of Health Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran Behzad Moradi Department of Surgical Technology, Faculty of Paramedicine, Lorestan University of Medical Sciences, Khorramabad, Iran Rasool Mohammadi Department of Epidemiology and Biostatistics, School of Public Health and Nutrition, Lorestan University of Medical Sciences, Khorramabad, Iran Maryam Saran Department of Radiology, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran Arash Ardalan Providence Saint Joseph Medical Center, Burbank, California, USA Noordin Mohammadi School of Nursing and Midwifery, Flinders University, Adelaide, Australia Tayebeh Cheraghian Shahid Rahimi Hospital, Lorestan University of Medical Sciences, Khorramabad, Iran 2019 09 19 2019 12 31 Background & Aim: This trial aimed to compare the pain relief and side effects of Oral Acetaminophen (OA) and Intravenous Acetaminophen (IVA) after CABG surgery. Methods & Materials: This parallel-group, triple-blinded, randomized trial was conducted on 113 CABG patients from September 2017 through February 2018.  The samples were selected through blocked randomization and allocated into two groups using computer-generated. The participants administered 1gr oral (OA group, n=57) or intravenous Acetaminophen (IVA group, n=56) every 6h for the first 24h following surgery; also, pain controlled in both group with Morphine multimodal analgesia strategy. Pain intensity measurement by VAS was followed after extubating the endotracheal tube at the 0, 1, 6, 12, 18 and 24 hours during the rest and deep breathing. The Morphine consumption and the incidence of nausea and vomiting in the first 24h were assessed. Data were analyzed using SPSS software and Chi-square, t-test, mixed ANOVA and ANCOVA test. Results: The pain score in the IVA group was found to be statistically significantly lower than the OA group at rest (P<0.001) and during deep breathing (P<0.001) in the first 24h. There was no statistically significant difference between groups regarding the cumulative Morphine consumption (P=0.056). The use of IVA was associated with a reduction in frequencies of nausea and vomiting incidents (P=0.029). Conclusion: Administration of IVA for the management of postoperative pain in CABG patients significantly reduced pain score and incidence of nausea and vomiting compared to OA. Any reduction in cumulative Morphine consumption did not accompany the lower pain. https://npt.tums.ac.ir/index.php/npt/article/view/776 https://npt.tums.ac.ir/index.php/npt/article/download/776/439