Meta-analysis of the use of rescue antiemetics following PONV prophylactic failure with 5-HT3 antagonist/dexamethasone versus single-agent therapies

OBJECTIVE: To assess the use of rescue antiemetic medication following 5-HT3 receptor antagonist (5-HT(3)RA) plus dexamethasone therapy versus monotherapy with a 5-HT3RA for prophylaxis of postoperative nausea and vomiting (PONV). DATA SOURCES: Reports of randomized, controlled trials were identified via a MEDLINE search (1966-September 2005) using the key terms ondansetron, dolasetron, tropisetron, granisetron, 5-HT3, PONV, vomiting, emesis, and nausea. STUDY SELECTION AND DATA EXTRACTION: Randomized, controlled trials of adult populations that had treatment arms comparing 5HT(3)RA/dexamethasone combination therapy with 5-HT3RA or dexamethasone monotherapies versus placebo or 5-HT3RA versus dexamethasone or placebo were selected for analysis. Another criterion was that a proportion of patients required rescue medication 48 hours or less following surgery. DATA SYNTHESIS: Odds ratios (ORs) with 95% confidence interval were calculated to determine incidence rates for use of rescue medications within early (0-6 h), late (6-24 h), and overall (0-24 or 48 h) postoperative periods. Overall effect sizes were calculated by pooling ORs within fixed and random effects models. CONCLUSIONS: Prophylaxis with 5-HT(3)RA/dexamethasone was associated with lower use of rescue antiemetics than 5-HT3RA (ORpooled = 0.48; 95% CI 0.29 to 0.77) or dexamethasone (ORpooled = 0.26; 95% CI 0.12-0.57) monotherapy during the overall postoperative period. Insufficient data were available to assess rescue use during early or late postoperative periods. It appears that patients at high risk of PONV who are treated prophylactically with combination 5-HT(3)RA/dexamethasone therapy are overall less likely to require rescue medication than if treated with 5-HT3RAs or dexamethasone alone. Additional large prospective studies are needed to determine the optimal regimen and timing of administration of prophylactic antiemetic therapy for different surgical populations.