Dexamethasone prevents postoperative nausea and vomiting: benefit versus risk.

Postoperative nausea and vomiting (PONV) is a common annoying experience after surgery. The overall incidence of PONV in adults is 20-30%; the incidence rate in patients of high-risk groups can be as high as 70-80%. Children are not exempted from attacking either; the incidence rate in children above the age of 3 is more than 40%. The incidence slowly drops after puberty, sharing the same rate with adults. Dexamethasone can be effective in preventing PONV in adults and children. Compared with other preventive medications, dexamethasone has equal or even better efficacy in reducing the incidence of PONV and has the advantages of low cost and longer effectiveness as well. Although the action mechanism of dexamethasone is hitherto not fully understood, animal studies have confirmed that the vomiting center in the brain stem plays a central role. A combination of dexamethasone with other antiemetics is more effective than any single drug alone. Additionally, the use of dexamethasone to prevent nausea and vomiting triggered by intravenous or epidural morphine for pain control can also offer a good therapeutic effect. To date, clinically, dexamethasone as a preventative drug against PONV has not caused fatal outcome; therefore, it is generally considered to be an effective and safe antiemetic. Nevertheless, its use in this regard may lead to adverse effects, principally postoperative hyperglycemia and infection.