Evaluation of the pre-emptive analgesic effects of ketamine hydrochloride versus magnesium sulphate in patients undergoing elective abdominal surgeries

Aim: To evaluate the Pre-emptive analgesic effects of Ketamine hydrochloride versus Magnesium sulphate in patients undergoing elective abdominal surgeries compared to control group. Method: In this study, 90 patients of age 18-70 years undergoing elective abdominal surgeries were randomly allocated into 3 groups of 30 each. Group K received inj. ketamine hydrochloride (0.5 mg/kg), Group M received inj. magnesium sulphate (50 mg/kg) and Group C received normal saline after induction and before surgical incision. Postoperative hemodynamic changes, Visual Analog Scale (VAS) score at 0, 1, 4, 6, 12, and 24 hrs; time of first rescue analgesia, the total amount of analgesia consumed, and adverse effects were recorded. Result: The VAS scores at all-time intervals were significantly higher in Group C compared to Groups K and M. Time for first rescue analgesia was significantly longer in Groups K and M as compared to Group C (p<0.0002). The consumption of Tramadol HCL was significantly lower in Groups K and M (233.00±72.19 and 233.33±97.10 mg) as compared to Group C (370.00±90.25) (P value <0.0001) without any significant side effects. The haemodynamic parameters in Group C showed a higher value at the 2nd hour. However, there were no significant differences between Groups K and M with respect to any parameter studied. Conclusion: A single Pre-emptive bolus dose of NMDAR antagonists like Ketamine or Magnesium is an easy and reliable method to provide better pain relief after elective abdominal surgeries without any adverse effects.