The objective of this study is to investigate if aprepitant in association with palonosetron and dexamethasone could reduce the incidence of PONV in high-risk patients for this symptom, undergoing cancer surgery mastectomies.

Postoperative nausea and vomiting (PONV) is a common anesthetic complication that occurs in approximately 30% of the surgical population and can reach up to 70% in high risk patients for PONV. Advances have been made to prevent PONV, but the incidence is still high in certain groups of patients. In high risk patients, pharmacologic intervention should consist of multimodal therapy, targeting different mechanisms of action. The objective of this study is to investigate if aprepitant in association with palonosetron and dexamethasone could reduce the incidence of PONV in high-risk patients for this symptom, undergoing cancer surgery mastectomies. METHODS: this is a randomized and double blind clinical trial. Female high-risk patients for PONV(Apfel score 3 or 4) scheduled for mastectomy that agree with the study and signed the informed consent, are randomly distributed into one of two groups: Group A, aprepitant 80 mg per os one hour before the surgery and Group B will receive placebo by the same route one hour before surgery, in a blinded way. After induction of anesthesia, dexamethasone 4 mg and palonosetron 0,075mg are intravenously administered to all patients. After the end of the surgery, a patient-controlled analgesia (PCA) device will be intravenously inserted in all patients. In the postoperative period, patients will be evaluated for nausea, vomiting and pain intensity in the recovery room and after 24 hours

Inclusion Criteria:

• patients submitted to breast cancer surgery
• non smokers

Exclusion Criteria:

• any contraindication to one of the drugs
• mental disease
• inability to understand the method or refusal to participate in the research