Mirtazapine administered preoperatively effectively reduced postoperative nausea and vomiting compared with placebo, and may have similar efficacy to ondansetron, according to results from a meta-analysis published in the Journal of PeriAnesthesia Nursing.

Investigators reviewed 7 randomized controlled trials to compare the efficacy of preoperative mirtazapine vs preoperative placebo or no treatment, as well as another antiemetic for postoperative nausea and vomiting. Secondary outcomes measured postoperative pain, morphine consumption, preoperative anxiety, pruritus, and adverse events including sedation and dry mouth.

In 3 of the reviewed studies, mirtazapine reduced postoperative nausea and vomiting by 56% (risk ratio [RR], 0.44) compared with placebo. In another study comparing mirtazapine with ondansetron, a 4% relative risk reduction (RR, 0.96) was seen, suggesting similar efficacy between the two. No differences in the incidence of postoperative pain or use of morphine were observed.

Compared with placebo and ondansetron, mirtazapine reduced the incidence of pruritus by nearly 35% (RR, 0.65 and 0.64, respectively).

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In addition, mirtazapine reduced preoperative anxiety compared with placebo or ondansetron; however, sedation was significantly associated with mirtazapine (RR, 22.47). No significant differences for dry mouth were reported.

“Further studies are needed to investigate comparative effects with other antiemetics, improve methodological conduct, and determine whether the sedative effects of mirtazapine affect clinically important outcomes such as respiratory depression,” the investigators concluded.

ReferenceBhattacharjee D, Doleman B, Lund J, Williams J. Mirtazapine for postoperative nausea and vomiting: systematic review, meta-analysis, and trial sequential analysis [published online March 14, 2019]. J Perianesth Nurs. doi: 10.1016/j.jopan.2018.11.006