Comparing the effect of preemptive intravenous acetaminophen and ketamine on postoperative pain

Abstract

Background: One of the most important problems after surgeries is postoperative pain that effect on patient, his family and hospital staff. Preemptive analgesia is a new method for control and prevention of this problem. This study was done to compare the preemptive effect of interavenous acetaminophen and ketamine on postoperative pain. Methods: In a double-blind randomized clinical trial study, 86 patients under lower extremity surgeries with ASA (American Society of Anesthesiologists) class I or II, at the age range of 15-70 years were selected and randomly divided in the two groups. The groups received 0.3 mg/kg ketamine or 15 mg/kg acetaminophen intravenously before anesthesia. Postoperative pain, immediately after the surgery, and 6, 12, 24 and 48 hours later was measured via visual analog scale (VAS). Besides, need to opioid drugs and postoperative complications were recorded. Findings: The mean ± SD postoperative pain in acetaminophen and ketamine groups was 3.8 ± 1.6 and 6.6 ± 1.6 at the end of the recovery, 2.5 ± 1.4 and 4.7 ± 1.5 at 6 hours later, 1.5 ± 1.2 and 2.8 ± 1.3 at 12 hours later and 0.6 ± 0.8 and 1.7 ± 1.3 at 24 hours later, respectively; the difference between the two groups was statistically significant in all times (P < 0.001). In addition, the mean changes of pain until 24 hours after the surgery were different between the two groups (P < 0.001). The mean of opioid used was not different between the two groups (P = 0.37). Conclusion: Using intravenous acetaminophen, as a preemptive, can decrease intensity of postoperative pain and decrease nausea and the need to opioid, and used narcotic. Besides, it has lower side effects compared to ketamine. © 2015, Isfahan University of Medical Sciences(IUMS). All rights reserved.