Perioperative antiemetic efficacy of dexamethasone versus 5-HT3 receptor antagonists: a meta-analysis and trial sequential analysis of randomized controlled trials.

Background: Dexamethasone has many desirable pharmacologic properties for perioperative use. Its antiemetic potential has been a focus of many recent trials.
Methods: Trials comparing dexamethasone to 5-HT3-receptor antagonists (5HT3-RA) for 24 h postoperative vomiting incidences published till August 2017 were searched in the medical database. Comparisons for antiemetic efficiency variables (vomiting incidence, nausea incidence, rescue antiemetic need, and patients with complete response) during early (until 6 h) and late postoperative phase were made. Comparative analgesic requirements were also evaluated.
Results: Twenty randomized controlled double-blinded trials were included in the final analysis. Twenty-four-hour vomiting incidence was similar (Fixed-effects, P = 0.86, I ²  = 2.94%). Trial sequential analysis (TSA) confirmed non-inferiority of dexamethasone for 24-h vomiting incidence. (α = 5%, β = 20%, δ = 10%) with "information size" being 1619 (required > 573). Equivalence was also verified from early and delayed nausea rate as well using TSA. Pooled results did not demonstrate superiority/inferiority of 5-HT3-RAs over dexamethasone in all other antiemetic efficacy variables (early and delayed). Heterogeneity was found to be low in all of the comparisons. Linear-positive dose-response curve for dexamethasone 24-h vomiting and nausea incidence was seen (correlation coefficient being 0.21 and 0.28, respectively). Dexamethasone reduced the analgesic need (MH-odds of 0.64 (95% CI being 0.44 to 0.93) P = 0.02, I2 = 0)). Possibility of publication bias could not be ruled out (Egger's test, X-intercept = 1.41, P = 0.04).
Conclusions: Dexamethasone demonstrates equal antiemetic efficacy compared to 5-HT3 receptor antagonists. The agents perform equally well both in early postoperative phase and up to 24 h after surgery. Use of dexamethasone replacing 5-HT3 RAs offers an additional advantage of lowering the opioid requirements during the perioperative period.