Background: The aim of the present study is to evaluate the effect of preoperative 0.5 mg/kg i.v. dexamethasone in combination with 0.5 mg/kg i.v. ketamine on pain, early oral intake and vomiting in pediatric patients undergoing tonsillectomy during the first 24 hours of the postoperative period. Methods: One hundred twenty children who were scheduled for tonsillectomy were randomly assigned to receive a single dose of dexamethasone 0.5 mg/kg i.v. as Group D (n = 30), receive ketamine 0.5 mg/kg i.v. as Group K (n = 30), receive dexamethasone 0.5 mg/kg i.v. and ketamine 0.5 mg/kg i.v. as Group KD (n = 30) and an equivalent volume of saline as Group C (n = 30) 15 minutes before the induction of anesthesia. Post-operative pain was evaluated using an observational pain score (OPS) on arrival to the post-anesthesia care unit (PACU), at 15, 30, 45, and 60 minutes after that and at 1, 2, 4, 6, 12, and 24 hours after arrival to the ward. Results: OPS scores were significantly lower at the time of arrival to the PACU, and at 15, 30, 45, and 60 minutes in the Group KD compared with Group C (p < 0.05). Postoperative OPS scores were significantly lower at 1, 2, 4, 6, 12, and 24 hours after operation in Group KD compared with Group C (p < 0.05). Conclusion: A prophylactic preoperative single dose of i.v. 0.5 mg/kg dexamethasone in combination with a single dose of i.v. 0.5 mg/kg ketamine significantly decreased post-tonsillectomy pain compare with using i.v. ketamine or i.v. dexamehasone separately.
Key words: Pain, Postoperative, Tonsillectomy, Dexamethasone, Ketamine.