Asociate Professor, Deartment of Anesthesiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

Background: Nausea and vomiting are common post operative complications which prevalence defere due to kind of surgery, kind of anesthesia drug, age, and sex between 20-80%. These complications can make problems such as increasing intracranial pressure, increasing intraoccular pressure, opening operation sutures, aspiration, etc. In some researches, the effect of midazolam in decreasing of vomiting and nausea is proved but there is not any research about the effect of combinating this drug with other drugs. This study aimed to compare the effect of midazolam alone and combination of midazolam and dexamethasone on decreasing postoperative nausea and vomiting.Methods: This clinical trial was done on 2 groups of 33 patient condidated of mastoidectomy at Azahra and Kashani hospitals in Isfahan, Iran. Men and women in ASA classes I and II were divided randomly to 2 groups. Group A recieved 0.075 mg/kg midazolam and group B received 0.075 mg/kg midazolam with 0/05 mg/kg dexamethasone after induction. The severity of nausea by visual analogue scale and number of vomiting were assessed at recovery ward and during 24 hours and were analyzed by t-test.Finding: In recovery ward, the mean score of nausea was 0.88 and 0.48 (P = 0.22) and the mean number of vomiting was 0.09 and 0 (P = 0.039) in groups A anb B, respectively. In first 6 hours, the mean score of nausea was 3.15 and 2.15 (P = 0.14) and the mean number of vomiting was 0.85 and 0.6 (P = 0.26) in groups A anb B, respectively. In second 6 hours, the mean score of nausea was 2.24 and 1.7 (P = 0.3) and the mean number of vomiting was 1.09 and 0.3 (P = 0.04) in groups A anb B, respectively. In second 12 hours, the mean score of nausea was 1.39 and 0.42 (P = 0.049) and the mean number of vomiting was 0.42 and 0.03 P = 0.047) in groups A anb B, respectively. The mean dose of metoclopramid used was 0.51 and 0.51 (P = 0.5) and 12.9 and 6.48 (P = 0.075) at recovery ward and during 24 hours, respectively. The mean time recovery ward hospitalization was 67.8 and 61.3 minutes in groups A anb B, respectively (P = 0.003).Conclusion: Nausea and vomiting in group received midazolam and dexamethasone was less than the group received midazolam alone, particularly in long time.