Effect of ondanstron and dexametasone on post operative nausea and vomiting in paients undergoing laparascopic cholecystectomy

INTERVENTION: Combination of Ondansetron, 4mg, as well as Dexamethasone, intravenously, immediately before receiving general anesthesia dexamethasone, 8mg, intravenously, immediately before receiving general anesthesia Intervention 1: Ondansetron, 4mg, intravenously, immediately before receiving general anesthesia. Intervention 2: dexamethasone, 8mg, intravenously, immediately before receiving general anesthesia. Intervention 3: Combination of Ondansetron, 4mg, as well as Dexamethasone, intravenously, immediately before receiving general anesthesia. Ondansetron, 4mg, intravenously, immediately before receiving general anesthesia Treatment ‐ Drugs CONDITION: nausea and vomiting. ; Vomiting following gastrointestinal surgery Vomiting following gastrointestinal surgery PRIMARY OUTCOME: Nausea and vomiting. Timepoint: 6 hours and 24 hours after intervention. Method of measurement: Questionnaires and observation. SECONDARY OUTCOME: Duration of anesthesia. Timepoint: Operation from start to end. Method of measurement: Per minute. INCLUSION CRITERIA: INCLUSION CRITERIA: age between 20‐65 years old, referring for elective laparascopic cholecystectomy Excluding criteria: Having nausea and/ or vomiting, taking any antiemetic medication within 48 hrs before surgery, having taken H2 blockers, having a history of motion sickness, pregnancy, menstruation, renal disease with high BUN and Cr, receiving any investigational drug within 30 days prior to the surgery, requiring open approach during Laparoscopic approach