ORIGINAL ARTICLE Willingness to Undergo Split-Dose Bowel Preparation for Colonoscopy and Compliance with Split-Dose Instructions R. Zackary Unger • Sable P. Amstutz • Da Hea Seo • Melanie Huffman • Douglas K. Rex Received: 6 October 2009 / Accepted: 3 December 2009 / Published online: 16 January 2010 Ó Springer Science+Business Media, LLC 2010 Abstract Background Split-dose bowel preparations for colonos- copy have superior effectiveness compared with giving all the preparation the evening before colonoscopy. Some physicians believe that split-dose preparations would be unpopular with patients scheduled for early morning colonoscopies. Aims To determine the willingness of potential patients to undergo split-dose bowel preparation for colonoscopy and the actual adherence of colonoscopy patients to split-dose instructions. Methods We performed a survey of esophagogas- troduodenoscopy patients and drivers of colonoscopy patients asking whether they would accept split-dose preparations for early morning colonoscopy appointments. We also asked colonoscopy patients scheduled in the early morning if they had complied with the written preparation instructions. Results Of the 300 individuals surveyed, the majority (85%) stated they would be willing to get up during the night to take the second dose of preparation. Of 107 colonoscopy patients with early morning appointments, 78% actually got up during the night to take the second dose of preparation. Conclusions Acceptance of and compliance with split-dose bowel preparations is high and should not be a deterrent to prescribing split-dose preparations for colonoscopy. Keywords Colonoscopy Á Bowel preparation Á Split dosing Introduction Effective bowel preparation is critical to optimal perfor- mance of colonoscopy. Ineffective preparation results in detection of fewer small polyps [1], flat polyps [2], and large polyps [3], as well as increased costs [4] and longer procedures [3, 4]. Ten different studies have directly tested whether bowel preparation is optimized by administration of either split doses or administration of the entire preparation on the day of examination [2, 5–13]. Split dosing refers to giving part of the preparation the evening before colonoscopy and the other part on the day of colonoscopy. Each of these ten studies found that administration of part or all of the prep- aration on the day of colonoscopy was superior to giving all of the preparation the evening before colonoscopy [2, 5– 13]. While the effectiveness of split dosing is well estab- lished, it is often not used in clinical practice [14]. Split dosing is not used in some practices because of restrictions placed on ingestion of fluids on the day of examination. However, the American Society of Anesthesiologists’ guidelines on fasting prior to sedation allow ingestion of clear liquids up until 2 h before sedation [15]. A second objection to split dosing is the belief that patients scheduled for early morning procedures would be unwilling to get up during the night to take the second dose of laxatives [16]. R. Z. Unger Á S. P. Amstutz Á D. H. Seo Á M. Huffman Á D. K. Rex Department of Medicine, Division of Gastroenterology/ Hepatology, Indiana University Medical Center, Indianapolis, IN, USA D. K. Rex (&) Indiana University Hospital #4100, 550 N. University Boulevard, Indianapolis, IN 46202, USA e-mail: drex@iupui.edu 123 Dig Dis Sci (2010) 55:2030–2034 DOI 10.1007/s10620-009-1092-x