title: Low-volume PEG plus ascorbic acid versus high-volume PEG as bowel preparation for colonoscopy.
abstract: OBJECTIVE
  High volumes of polyethylene glycol (PEG)-based solutions as bowel preparation for colonoscopy are effective, but often poorly tolerated. To compare a 2 l PEG-based solution combined with ascorbic acid (PEG + Asc) with 4 l PEG-based solution (PEG).
  
  
  METHODS
  In a single blind, quasi-randomized, prospective study, 350 patients undergoing colonoscopy received 2 l of PEG + Asc or 4 l of PEG. For morning procedures, the total dose of PEG + Asc was taken the evening before, for afternoon colonoscopies, PEG + Asc was given as a split dose. The 4 l PEG preparation was given as a split dose. Efficacy of preparation was scored on a five-point scale in three different colon segments. Patients' experiences were evaluated using a questionnaire.
  
  
  RESULTS
  From 307 patients (149 PEG + Asc, 158 PEG), results were available. Successful colon cleansing was achieved in 90.6% in the PEG + Asc group compared to 96% in the PEG group (not significant). In patients prepared with PEG + Asc, bowel cleansing was worse when patients underwent colonoscopy in the morning, compared to afternoon procedures. Side-effects and patients' experiences were similar in the PEG + Asc and PEG group.
  
  
  CONCLUSIONS
  Low-volume PEG + ascorbic acid has comparable efficacy and tolerability as high-volume PEG solution. The cleansing results were worse if patients received the full dose PEG + Asc the evening before the procedure compared to the split dose. Our data support the administration of PEG + Asc as a split dose before the procedure.
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands. s.corporaal@mdl.umcg.nl
authors.forename: Sietske
authors.initials: S
authors.lastname: Corporaal
authors.forename: Jan H
authors.initials: JH
authors.lastname: Kleibeuker
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Koornstra
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000008:administration & dosage; D001205:Ascorbic Acid / Q000008:administration & dosage*; D003113:Colonoscopy / Q000379:methods*; D004334:Drug Administration Schedule; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D011092:Polyethylene Glycols / Q000008:administration & dosage*; D011446:Prospective Studies; D015203:Reproducibility of Results; D013501:Surface-Active Agents / Q000008:administration & dosage; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D000975:Antioxidants; D004338:Drug Combinations; C520497:MoviPrep; D013501:Surface-Active Agents; D011092:Polyethylene Glycols; D001205:Ascorbic Acid