Premedication With Oral Dextromethorphan Reduces Intra-Operative Morphine Requirement



Talakoub R^{1, 2} ; Molaeinasab F¹ Show Affiliations
Source: Journal of Research in Medical Sciences Published:2005

Abstract

Background: Intra-operative pain has adverse effects on hemodynamic parameters. Due to complications of opioids for pain relief, using non-opioids medication is preferred. The purpose of this study was to investigate the effect of oral dextrometorphan premedication on intra-operative Morphine requirement. Methods: After approval of the Ethics committee and informed consent, 40 adult patients who stand in American Society of Anesthesiologists Physical Status I and II, under general anesthesia for elective laparatomy were selected and classified in two equal groups randomly. In group A, oral dextromethorphan (60mg) was administered at 10 PM and 6 AM preoperatively. In group B, placebo (dextrose) was administered. After induction of general anesthesia and before skin incision, intravenous morphine (0.01 mg/kg) was administered. During surgery, when systolic blood pressure or heart rate was increased more than 20% of the preoperative baseline, 0.01 mg/kg morphine was administered. At the end of surgery, the totally prescribed morphine (mg/kg) and maximal increase, in systolic, diastolic, mean arterial blood pressure and heart rate relative to the baseline values were calculated and statistically compared with student's t-test. Results: The mean dose of administered morphine during surgery was significantly less in group A than group B (P<0.0001). Also, Maximal increase in systolic, diastolic and mean arterial blood pressure was significantly less in group A (p<0.003, p<0.004, p<0.0001, respectively). There was no significant difference in maximal heart rate increase between two groups (p<0.114). Conclusion: Oral dextromethorphan premedication may decrease intra-operative morphine requirement and reduce maximal increase in systolic and mean arterial blood pressure during surgery.