Randomized, controlled comparison of two forms of preparation for screening flexible sigmoidoscopy

Am J Gastroenterol. 1997 May;92(5):809-11.


Objective: There is a paucity of data regarding the optimal form of bowel preparation for flexible sigmoidoscopy. Most endoscopists recommend enemas. A simpler preparation that is easy, acceptable, and that reduces patient encounter time would be desirable, and might be cost-effective. Our objective in this study was to evaluate a simple oral form of preparation for screening flexible sigmoidoscopy.

Methods: In this randomized, single-blind, controlled trial, we compared two forms of preparation in consecutive male patients referred for screening flexible sigmoidoscopy. The oral preparation consisted of one bottle of magnesium citrate and two "Dulcolax" tablets on the evening before flexible sigmoidoscopy. This was compared with the standard form of preparation, namely, two Fleet's enemas given on arrival at the endoscopy suite. Thirty-seven patients received the oral preparation [mean age, 62.8 +/- 8.9 (SD) yr]; 33 received enemas (mean age, 65.2 +/- 7.3 yr). Endoscopists were blinded to the preparation.

Results: Mean time between arrival and starting flexible sigmoidoscopy was 36 +/- 22 (SD) min for patients on oral preparation, and 62 +/- 25 min for patients receiving enemas (p < 0.0001). Mean times performing flexible sigmoidoscopy were 10 +/- 3 min and 13 +/- 4 min, respectively (p = 0.004). Mean patient satisfaction score (range 0-13) was higher for patients given the oral preparation (11.4 +/- 1.8) than for patients receiving enemas (9.6 +/- 2.4) (p = 0.001). Fifteen patients randomized to receive the oral preparation had previous flexible sigmoidoscopy with an enema preparation; all preferred the oral form. Mean technical difficulty (range 1-10) was 3 +/- 2.2 for patients given the oral preparation and 4.9 +/- 3.1 for patients receiving the enema preparation (p = 0.01). Polyps were identified in 10/37 patients who received the oral preparation and in 3/33 patients who received enemas (p = 0.05). Quality of colon preparation was judged "good" in 29, "fair" in four, and "poor" in four, among the 37 patients given the oral form; corresponding values for 33 patients given enemas were 16, 10, and 7 (p = 0.03).

Conclusion: Patient acceptance, encounter time, technical ease, and quality of colon preparation were significantly better with the oral form of colon preparation than with the standard Fleet enema preparation.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Administration, Oral
  • Aged
  • Bisacodyl / administration & dosage*
  • Cathartics / administration & dosage*
  • Citrates / administration & dosage*
  • Humans
  • Magnesium Compounds / administration & dosage*
  • Male
  • Mass Screening*
  • Middle Aged
  • Patient Satisfaction
  • Phosphates / administration & dosage*
  • Sigmoidoscopy*
  • Single-Blind Method
  • Treatment Outcome


  • Cathartics
  • Citrates
  • Magnesium Compounds
  • Phosphates
  • Bisacodyl
  • sodium phosphate