en Infectious Diseases Infectious Diseases Original Article Original Article Background: Postoperative nausea and vomiting is a high unpleasant symptom in surgical procedures. This study compares the effectiveness of midazolam with promethazine as multipurpose drug in postoperative nausea and vomiting as a preoperative and anesthetic medication after appendectomy. <br>Methods: This randomized, double – blind clinical trial study was performed in patients who underwent appendectomy. These patients randomly received either placebo or midazolam or promethazine 5 minutes before appendectomy. All episodes of vomiting and nausea within 24 hours after surgery were recorded. The study population (N=75) comprised 3 comparable subgroups (N=25 in each group). A standard general anesthetic technique and postoperative analgesia were used. The data were collected and analyzed. <br>Results: Vomiting and nausea occurred in 19.20%, 0% and 81.80% of the patients in the midazolam, promethazine and placebo groups, respectively. The frequency of postoperative nausea and vomiting was as follows: the first 6 hours after surgery 0%, 0% and 50%, during the second 6 hours after surgery 19%, 0% and 19%, during the third 6 hours after surgery 0%, 0% and 7%, during the fourth 6 hours after surgery 0%, 0% and 4% in the midazolam, promethazine and placebo groups, respectively. There were no significant differences between promethazine with midazolam in reduction of postoperative nausea and vomiting. <br>Conclusion: Our study suggests that midazolam can be used as multipurpose drugs in postoperative nausea and vomiting as a preoperative medication after appendectomy and treatment using midazolam for anti-emetic, prophylaxis provide a similar effect compared to promethazine in the present study. Midazolam, Postoperative nausea have vomiting, Promethazine 270 273 http://caspjim.com/browse.php?a_code=A-10-62-59&slc_lang=en&sid=1 Nasrin Shirdashtzadeh 1003194753284600460 1003194753284600460 Yes Nazanin Eshraghi 1003194753284600461 1003194753284600461 No Azadeh Eshraghi 1003194753284600462 1003194753284600462 No