Laparoscopic sleeve gastrectomy (LSG) is an emerging treatment modality among the various types of surgical approach to obesity (1). The incidence of PONV in obese patients undergoing bariatric surgery, who did not receive antiemetic prophylaxis, is high at nearly 70-80 % (2,3). Postoperatively, bariatric patients appear to suffer from nausea and vomiting more frequently than normal weight or obese patients.

Currently, available interventions for PONV prophylaxis, especially as monotherapy, lack universal efficacy. Use of combination therapies with different pharmacological basis is likely to bring down rates of PONV. (6) Intravenous dexamethasone (8-10mg) reduces the incidence of PONV, minimizing activity of phospholipase A2 and blocking the expression of cyclooxygenase (COX)2 mRNA that reduce production of prostaglandin and control the release of endorphins.

Aprepitant has demonstrated powerful additive effects when combined with dexamethasone and a 5-HT3 to prevent both acute and delayed chemotherapy-induced nausea and vomiting (CINV), and in the prevention of postoperative nausea and vomiting (PONV) The use of mirtazapine in the management of nausea and vomiting has been reported for both treatment and premedication

Inclusion Criteria:

• ASA physical status I or II
• Body mass index (BMI) ≥ 35 kg/cm-2

Exclusion Criteria:

• Patients with gastrointestinal disorders,
• Patients with significant major organ disease,
• Patients received antidepressant drugs,
• Patients received an anti-emetic drug within 48 h before surgery,
• Patients on treatment with systemic glucocorticoids within 4 weeks before surgery.