Postoperative nausea and vomiting (PONV) is a major cause of morbidity in surgical patients. Several factors including age, gender, type of surgery and anesthetic agents, intraoperative opioid use, and duration of anesthesia, have been implicated as the causes of PONV. Variety of new drugs and anesthetic techniques has been introduced in the recent past to reduce PONV; however, the incidence still remains significantly high, ranging between 25% and 30% even after multimodal antiemetic regimens.

Breast surgery is associated with high incidence of PONV, ranging between 15% and 84%. Oncologic breast surgical procedures have been reported to have increased incidence of PONV. Patients with no known risk factors carries 10% risk of PONV and it increases exponentially to 61% and 79%, respectively, when 3 or 4 risk factors exist (female gender, nonsmoker, history of motion sickness, postoperative opioid use and a history of PONV).

In the recent times, studies have demonstrated the relationship between substance P, the CNS and emesis center. A new class of non-peptide neurokinin1 receptor antagonists (NK1RAs), demonstrated to have activity against both peripheral and central emetic stimuli. Human trials have examined NK-1 antagonists in the prevention of PONV, showing a decreased incidence. Aprepitant may have antiemetic effects beyond 48 h after surgery with special impact on post-discharge nausea and vomiting. Aprepitant, a highly selective, brain-penetrant NK-1 RA with a long half-life and preclinical efficacy against opioid-induced emesis, has demonstrated efficacy against chemotherapy-induced nausea and vomiting when combined with other antiemetic, and is the first in its class to be approved for this indication. NK-1 RA have been studied for prevention of PONV in abdominal and gynecological surgery and found to be effective but no literature is available regarding its use in breast cancer patient.  Considering the fact that breast cancer patients are at high risk of PONV, we planned this study of Aprepitant versus Dexamethasone for Preventing Postoperative Nausea and Vomiting in Breast Cancer Patients undergoing surgery.