Prophylaxis of postoperative nausea and vomiting in patients scheduled for breast surgery.

Breast surgery performed under general anaesthesia is associated with a high incidence of postoperative nausea and vomiting (PONV). Between 60% and 80% of patients undergoing mastectomy (with axillary dissection) experience PONV. Pharmacological approaches have been investigated to reduce PONV after breast surgery. Traditional antiemetics (droperidol and metoclopramide) are frequently used for the prevention of PONV during the first 24 hours after anaesthesia. The available non-traditional antiemetics that have been shown to be effective for prophylaxis against PONV are dexamethasone, clonidine, propofol and supplemental oxygen. Antiserotonins (ondansetron, granisetron, tropisetron, dolasetron and ramosetron) are highly effective for preventing PONV for 24 hours postoperatively, compared with traditional antiemetics. Ramosetron is effective for the long-term (up to 48 hours) prevention of PONV. Better results can be obtained by combining antiemetics, because they have different sites of action. Combination antiemetic therapy is often effective for preventing PONV after breast surgery. Combinations of an antiserotonin (granisetron or dolasetron) and droperidol or dexamethasone are more effective than monotherapy with antiserotonins. A non-pharmacological technique is acupuncture at the P6 (Nei-Kuan) point. Overall, these pharmacological and non-pharmacological approaches reduce the incidence of PONV following breast surgery. Most of the published trials indicate improved prophylaxis of PONV following breast surgery by avoiding risk factors, and by using effective antiemetic agents in women scheduled for mastectomy (with axillary dissection). The clinician must weigh the benefits of using pharmacological and non-pharmacological approaches for PONV against the risk of occurrence of adverse events.