Dexamethasone for the prevention of postoperative nausea and vomiting: A quantitative systematic review

The role of dexamethasone in the prevention of postoperative nausea and vom iting (PONV) is unclear. We reviewed efficacy and safety data of dexamethas one for prevention of PONV. A systematic search (MEDLINE, EMBASE, Cochrane Library, hand searching,bibliographies, all languages, up to April 1999) wa s done for full reports of randomized comparisons of dexamethasone with oth er antiemetics or placebo in surgical patients. Relevant end points were pr evention of early PONV (0 to 6 h postoperatively), late PONV (0 to 24 h), a nd adverse effects. Data from 1,946 patients from 17 trials were analyzed: 598 received dexamethasone; 582 received ondansetron, granisetron, droperid ol, metoclopramide, or perphenazine; 423 received a placebo; and 343 receiv ed a combination of dexamethasone with ondansetron or granisetron. With pla cebo, the incidence of early and late PONV was 35% and 50%, respectively. S ixteen different regimens of dexamethasone were tested, most frequently, 8 or 10 mg IV in adults, and 1 or 1.5 mg/kg IV children. With these doses, th e number needed to treat to prevent early and late vomiting compared with p lacebo in adults and children was 7.1 (95% CI 4.5 to 18), and 3.8 (2.9 to 5 ), respectively. In adults, the number needed to treat to prevent late naus ea was 4.3 (2.3 to 26). The combination of dexamethasone with ondansetron o r granisetron further decreased the risk of PONV; the number needed to trea t to prevent late nausea and vomiting with the combined regimen compared wi th the 5-HT3 receptor antagonists alone was 7.7 (4.8 to 19) and 7.8 (4.1 to 66), respectively. There was a lack of data from comparisons with other an tiemetics for sensible conclusions. There were no reports on dexamethasone- related adverse effects. Implications: When there is a high risk of postope rative nausea and vomiting, a single prophylactic dose of dexamethasone is antiemetic compared with placebo, without evidence of any clinically releva nt toxicity in otherwise healthy patients. Late efficacy seems to be most p ronounced. It is very likely that the best prophylaxis of postoperative nau sea and vomiting currently available is achieved by combining dexamethasone with a 5-HT3 receptor antagonist. Optimal doses of this combination need t o be identified.