Best evidence in anesthetic practice: prevention: dimenhydrinate prevents postoperative nausea and vomiting.

Structured abstract Question: In patients undergoing surgery, does prophylactic dimenhydrinate reduce the frequency of postoperative nausea and vomiting (PONV) compared to placebo? Data sources: Studies were identified by computerized searches (MEDLINE, EMBASE, Cochrane Library) up to June 2001, citation review, and hand searches of locally available anesthesia journals. No language restrictions were applied. Study selection: Studies were selected if they were randomized controlled trials comparing prophylactic dimenhydrinate or diphenhydramine to placebo. Data extraction: Data was extracted in duplicate on postoperative nausea, postoperative vomiting, and PONV. Main results: Eighteen trials with a total of 3,045 patients met the inclusion criteria. Compared to placebo, dimenhydrinate reduced the frequency of early (0–6 hr postoperatively) PONV (relative benefit [RB] 1.21; 95% confidence interval [CI] 1.07–1.21) and overall (0–48 hr postoperatively) PONV (RB 1.51; 95% CI 1.27–1.78; Table). Dimenhydrinate reduced overall PONV in subgroups of adults, children, and routes of administration (iv/im or pr). Conclusion: Prophylactic dimenhydrinate reduces PONV up to 48 hr after surgery. Funding: Not reported. Correspondence: Dr. med. Peter Kranke, Department of Anesthesiology, University of Wuerzburg, Josef-Schneider-Str. 2, D-97080 Wuerzburg, Germany. E-mail: [email protected]