A randomized, double-blind, multicenter trial comparing transdermal scopolamine plus ondansetron to ondansetron alone for the prevention of postoperative nausea and vomiting in the outpatient setting.

[BACKGROUND] Postoperative nausea and vomiting (PONV) are common complications after ambulatory surgery. We sought to determine whether the use of transdermal scopolamine (TDS) in combination with IV ondansetron (OND) is more effective than one alone for reducing PONV in outpatient settings.

[METHODS] In a randomized, double blind, multicenter trial, 620 at-risk female patients undergoing outpatient laparoscopic or breast augmentation surgery received either an active TDS patch or a similar appearing sham 2 h before entering the operating room. All patients received IV OND (4 mg) 2-5 min before induction of anesthesia followed by a general anesthetic regimen. Complete antiemetic response, defined as no vomiting/retching or rescue medication use, was measured through 24 h and 48 h after surgery. The proportion of patients with vomiting/retching, nausea, or use of rescue medication, the time from the end of surgery to the first episode of these events and the time to discharge from the hospital/surgery center, as well as the number and severity of vomiting/retching and nausea episodes, and patient satisfaction with antiemetic therapy were also collected.

[RESULTS] The combination of TDS + OND statistically significantly reduced nausea and vomiting/retching compared with OND alone 24 h after surgery but not at 48 h. The proportion of patients who did not experience vomiting/retching and did not use rescue medication was 48% for TDS + OND and 39% for OND alone (P < 0.02). Total response (no nausea, no vomiting/retching, and no use of rescue medication) was also statistically higher for the TDS + OND group compared with the OND-only group (35% vs 25%, P < 0.01). The time to first nausea, vomiting/retching, or rescue episode was statistically significantly longer for the TDS + OND group compared with the OND-only group (P < 0.05). The cumulative overall incidence of adverse events was lower in the TDS + OND group compared with the OND group (36.7% vs 49%, P < 0.01).

[CONCLUSIONS] TDS + OND reduces PONV compared with OND alone. This is achieved with a reduction in adverse events.