BACKGROUND AND OBJECTIVES: It is calculated that the incidence of postoperative nausea and vomiting (PONV) is approximately 30%. The prophylaxis of PONV has been the subject of several studies, both to decrease this problem and to compare the cost-benefit ration of the treatment used. The objective of this study was to compare the efficacy of 5 antiemetic drugs with a control group in emergency appendectomy. METHODS: A controlled, double-blind, prospective study with 150 patients, ASA I and II, BMI < 30, undergoing appendectomy, was undertaken. Patients were divided in six groups: Group 1 (n = 25): 5 mL of normal saline; Group 2 (n = 25): 0.625 mg of droperidol; Group 3 (n = 25): 20 mg of metoclopramide; Group 4 (n = 25): 5 mg of tropisetron; Group 5 (n = 25): 1 mg of granisetron; Group 6 (n = 25): 4 mg of dexamethasone. Monitoring included ECG, non-invasive blood pressure, O2 saturation, PETCO2, anesthetic gas analyzer and peripheral nerve stimulator. The presence of PONV, complications and the degree of satisfaction in the first 48 hours were evaluated. RESULTS: The incidence of PONV in the droperidol group was 4% while in the granisetron, tropisetron and metoclopramide groups it was 12% (p < 0.05). The dexamethasone group had a 24% incidence and the control group 28%. CONCLUSIONS: Low doses of droperidol were more effective in the prophylaxis of PONV in emergency appendectomy than the other drugs. © Sociedade Brasileira de Anestesiologia, 2007. Indications:For the prevention of postoperative nausea and vomiting in 25 patients who underwent appendectomy. Patients:150 patients, age range 18-65 years. Navoban group: n=25, 12 males and 13 females, mean age 25.6 years. Droperidol group: n=25, 13 males and 12 females, mean age 26.5 years. Metoclopramide group: n=25, 14 males and 11 females, mean age 28.5 years. Granisetron group: n=25, 14 males and 11 females, mean age 31.1 years. Dexamethasone group: n=25, 11 males and 14 females, mean age 34.2 years. Control (normal saline) group: n=25, 12 males and 13 females, mean age 27.8 years. TypeofStudy:A study investigating the efficacy of Navoban, droperidol, metoclopramide, granisetron and dexamethasone for the prevention of postoperative nausea and vomiting (PONV) in patients who underwent appendectomy. Randomized, double blind, controlled, comparative clinical study. DosageDuration:5 mg in 5 mL of normal saline (NS) iv given before anesthesia induction. Duration not stated. ComparativeDrug:Droperidol dose was 0.625 mg diluted in 5 mL of normal saline, metoclopramide 20 mg, granisetron 1 mg and dexamethasone 4 mg; given iv before anesthesia induction. Duration not stated. Results:The incidence of PONV was 4% (n=1) in the droperidol group; 12% (n=3) in the granisetron, Navoban and metoclopramide groups, respectively; 24% (n=6) in the dexamethasone group, and 28% (n=7) in the control group. The frequency of nausea was remarkably greater in the control group than in the droperidol (p < 0.0001) and metoclopramide, Navoban, and granisetron groups (p < 0.001). The frequency of vomiting was greater in the control group than in the droperidol (p < 0.01) and metoclopramide, Navoban, and granisetron groups (p < 0.02). No adverse reactions occurred. There was no intra and postoperative cardiac arrhythmias. The degree of patient satisfaction was similar in the droperidol, Navoban and granisetron groups. AdverseEffects:No patient had intra and postoperative cardiac arrhythmia. AuthorsConclusions:Low doses of droperidol were more effective in the prophylaxis of PONV in emergency appendectomy than the other drugs. In this series of 150 patients, adverse reactions to the drugs or the presence of perioperative arrhythmias were not observed. FreeText:Concomitant drugs: anesthetic agents [lidocaine (1 mg/kg), fentanyl (2 mcg/kg), thiopental sodium (4 mg/kg), atracurium (0.4 mg/kg), mixture of 50% oxygen and nitrous oxide, and isoflurane] and postoperative analgesic agents (parenteral infusion of metamizol, intramuscular diclofenac sodium, and intravenous morphine as needed), and ranitidine (50 mg intravenously) was given for 48 hours.