Pilot Study of Ondansetron in Improvement of Pediatric Colonoscopy Preparation Outcomes at an Urban Academic Center

OBJECTIVES: To gather initial data on the effectiveness and tolerability of the addition of Ondansetron to bowel preparation regimens to justify a funded, larger, placebo-controlled study. METHODS: DESIGN, SETTING, AND PARTICIPANTS: A total of 41 pediatric and young adult (age 2–22) patients participated in a single center, open label, parallel randomized trial, with simple randomization. All patients were recruited as outpatients, and all procedures occurred as outpatient procedures, with both recruitment and procedures occurring at a low-resource urban academic medical center in Brooklyn. INTERVENTIONS AND OUTCOME MEASURES: The intervention studied was a single dose of oral-dissolving tablet Ondansetron provided before initiation of bowel preparation using a standardized prep of Polyethylene Glycol 3350 and Bisacodyl. There were 2 arms, a study arm using typical preparation (Polyethylene Glycol 3350 and Bisacodyl) and Ondansetron, and a control arm (Polyethylene Glycol 3350 and Bisacodyl). Patients received standard weight-based dosing. The primary outcome measure assessed was the Boston Bowel Preparation Scale (BBPS) to assess efficacy of preparation. Secondary objectives included evaluation of patient satisfaction via a survey answered by each patient. The questionnaire assessed the presence of the following symptoms during bowel prep: abdominal pain, nausea, bloating, vomiting, scale of ease/difficulty, and if the entire bowel prep was completed. RESULTS: No benefit to BBPS from the addition of Ondansetron to bowel preparation was observed. Statistically significant improvement in reports of abdominal pain (35% decrease in Ondansetron arm) was noted with a P = 0.019. No statistically significant improvement was noted in other symptoms although all domains showed nonsignificant improvement in the Ondansetron arm. CONCLUSION: No benefit to efficacy of preparation as measured by the BBPS was observed. A single dose of Ondansetron before bowel preparation reduced reports of abdominal pain by 35%, with other symptomatic improvements suggesting possible improvements to be confirmed by a higher-powered study. Trial registration: NCT05439772.