Chewing gum to treat postoperative nausea and vomiting in female patients: a multicenter randomized trial

Background Postoperative nausea and vomiting (PONV) is common after general anesthesia, with consequences for patient outcomes, satisfaction with care and healthcare costs. Our aim was to compare a new treatment, chewing gum, with a widely-used intravenous agent, ondansetron, to treat PONV in female patients in the post anesthesia care unit (PACU). Methods We conducted a multicenter, randomized, controlled non-inferiority trial in 17 hospitals in Australia and New Zealand. Female patients aged ≥12 years undergoing volatile anesthetic-based general anesthesia for laparoscopic or breast surgery were enrolled. Protocolized anti-emetic prophylaxis was administered. Patients who developed PONV in the PACU were randomized to either 15 min of chewing gum or 4 mg of intravenous ondansetron. The primary outcome was cessation of nausea, retching or vomiting, with no recurrence nor rescue medication for 2 h after administration of the randomized intervention (i.e., complete response). Results Of 865 enrolled patients, 218 were randomized. In a per-protocol analysis, 50 of 105 (47.6%) ondansetron-treated patients compared with 31 of 103 (30.1%) chewing gum-treated patients achieved the primary outcome (absolute risk difference [95% confidence interval (CI)] -17.3 [-30.4 to -4.3] %), not reaching our prespecified non-inferiority limit. Time to complete response was longer for patients randomized to chewing gum (hazard ratio [95% CI] 0.53 [0.34, 0.83]), and they were more likely to receive antiemetics in the 24 h after surgery (absolute risk difference [95% CI] 14.07 [1.65, 26.49]). Conclusions Chewing gum cannot be recommended as an alternative to ondansetron for treatment of PONV in female patients administered antiemetic prophylaxis.