Background: Dexmedetomidine possesses sedative and analgesic effects and is a selective α-2 adrenoceptor agonist. Researchers have been particularly curious about the role of ketamine in the contemporary opioid crisis. This study aimed to evaluate and compare between dexmedetomidine infusion versus ketamine infusion for reducing opioid consumption among obese patients undergoing abdominal surgeries.

Methods: We conducted this prospective double blinded randomized controlled trial on seventy-eight obese patients of class I&II undergoing abdominal surgeries. They were categorized in three groups (26 cases in each group): Group C (Control): received 0.9% normal saline, Group D (Dexmedetomidine): after bolus of 0.5 µcg/kg, they received dexmedetomidine infusion (4µcg/mL), Group K (Ketamine): after bolus of 0.3 mg/kg they received ketamine infusion (2 mg/mL). The intraoperative (total dose of fentanyl and hemodynamics) and postoperative (numeric rating scale (NRS), Modified Observer's assessment of alertness/sedation scale (MOAS/S) and rescue analgesic dose) were evaluated.

Results: The Dexmedetomidine group showed highly significant (p<0.001) better MOAS\S score than the other two groups immediately postoperative and then control group after 10 minutes. The Ketamine group had significant (p≤0.05) better NRS score than the Dexmedetomidine group at 6 and 12 hours. The Ketamine group needed highly significant (P ≤0.001) longer time to first require analgesic compared to the control group and significantly (P <0.05) longer than the Dexmedetomidine group.

Conclusion: Dexmedetomidine and ketamine could effectively aid in pain management among obese patients undergoing abdominal surgery.