Effectiveness of Low-Dose Ketamine and Intravenous Lidocaine Versus Fentanyl for Postoperative Pain

Patients in the treatment group will be administered through a Ketamine IV bolus of 0.5 mg/kg during the induction phase with propofol of 3 mg/kg, followed by a continuous infusion of ketamine of 0.2 mg/kg/hr. Before induction, a lidocaine bolus of 1.5 mg/kg will be given, and the same dose of lidocaine will be administered every 15 to 20 minutes after induction of anesthesia until the start of skin closure. Patients in control group will receive a conventional GA with fentanyl 2µg/kg given during induction of anesthesia and one fourth of initial dose of fentanyl will be given over 20-30 minutes.