Midazolam for Anxiolysis and Postoperative Nausea and Vomiting Prophylaxis: Can We Kill Two Birds with One Stone?

P ostoperative nausea and vomiting (PONV) remains the most common anesthetic-related complication in today's perioperative environment and one of the most feared outcomes by patients before surgery. 1 With better understanding of the multiple receptor pathways involved in the pathogenesis of PONV, we are now able to optimize the antiemetic prophylaxis in high-risk patients by using a multimodal approach that targets several different receptor systems. 2 However, in high-risk patients, studies using a multimodal approach incorporating total IV anesthesia with propofol and a combination of 2 or 3 antiemet-ics working at different receptors have reported a PONV incidence of approximately 20%. Therefore, the research is ongoing to find additional strategies that could be used to further reduce the incidence of PONV. Midazolam is widely used as an anxiolytic in both adult and pediatric patients. Some studies published >2 decades ago have suggested that benzodiazepines, including mid-azolam, might have antiemetic properties in the perioperative period 4 as well as in the management of chemotherapy-induced nausea and vomiting. So does this widely used anxiolytic provide a clinically useful antiemetic effect? In this issue of Anesthesia & Analgesia, the authors of 2 meta-analyses investigated the perioperative use of mid-azolam as a prophylactic antiemetic. The meta-analysis by Grant et al. 7 included 12 studies, whereas Ahn et al. 8 included 4 additional studies (2 that added midazolam to a postoperative patient-controlled analgesia regimen 9,10 and 2 tracked PONV as a secondary outcome that was not clearly noted in the abstract). The 12 studies included by both meta-analyses investigated the preoperative IV administration of midazolam in doses ranging from 40 to 75 μg/kg, whereas 2 of the studies included a dose 30 minutes before the end of surgery (1 of which also dosed midazolam at induction). All studies compared midazolam with placebo except for 3 studies included in both meta-analyses that studied the addition of midazolam to another antiemetic. The outcomes of both meta-analyses were postoperative nausea, postoperative vomiting, and PONV in the first 24 hours. In addition to the overall 24-hour analysis, the study by Ahn et al. also parsed the effect of midazolam into early (0–6 hours after surgery) and late (6–24 hours after surgery) time periods. Both meta-analyses were well conducted and suggest a substantial 38% to 55% reduction in the risk of overall PONV with the perioperative administration of midazolam and also showed a benefit in both early and late time …