Use of Prophylactic Ondansetron with Intravenous Opioids in Emergency Department Patients: A Prospective Observational Pilot Study.

BACKGROUND: The current literature suggests that the prophylactic use of antiemetics is ineffective at preventing nausea or vomiting caused by opioids in the emergency department (ED). While there is no data evaluating ondansetron's efficacy for preventing opioid-induced nausea and vomiting, this practice remains common despite a lack of supporting evidence.

OBJECTIVES: This study aimed to identify if prophylactic ondansetron administered with intravenous (IV) opioids prevents opioid-induced nausea or vomiting.

METHODS: This prospective observational study was conducted in the ED at two academic medical institutions. Patients were eligible for enrollment if they were prescribed an IV opioid with or without IV ondansetron and absence of baseline nausea. Patients' level of nausea was evaluated at baseline, 5 min, and 30 min after an IV opioid was administered and then observed for 2 hours.

RESULTS: One hundred thirty-three patients were enrolled, with 90% of patients presenting with a chief complaint of pain. Sixty-four (48.1%) patients received an IV opioid alone and 69 (51.9%) patients received both IV ondansetron and an IV opioid. Twenty-three (17.3%) patients developed nausea caused by opioid administration. One (0.75%) patient had an emetic event and 3 (2.3%) patients required rescue antiemetics during their observation period. Rate of nausea was similar between treatment groups 5 min after the opioid was administered (p = 0.153). There was no statistical difference in emesis, rescue medication requirements, or nausea severity between treatment groups.

CONCLUSION: Our trial found that ondansetron did not appear to be effective at preventing opioid-induced nausea or vomiting. These findings and previous literature suggest prophylactic ondansetron should not be given to ED patients who are receiving IV opioids.