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Bowel preparation before colonoscopy in adults

Yousif I A-Rahim, MD, PhD
Myron Falchuk, MD
Section Editor
John R Saltzman, MD, FACP, FACG, FASGE, AGAF
Deputy Editor
Kristen M Robson, MD, MBA, FACG


A successful colonoscopy requires an adequate preparation of the large bowel that facilitates clear visualization of the mucosal surface. The effectiveness of the bowel preparation is a critical factor related to the safety, diagnostic accuracy, quality, difficulty, and speed of the examination.

This topic will discuss the methods for bowel preparation for outpatient colonoscopy and will provide recommendations for addressing commonly encountered problems. An overview of colonoscopy in adults is discussed separately. (See "Overview of colonoscopy in adults".)

The approach to bowel preparation for colonoscopy in the setting of acute gastrointestinal bleeding is discussed separately. (See "Approach to acute lower gastrointestinal bleeding in adults", section on 'Colonoscopy'.)

Society recommendations for bowel preparation include a guideline from the US Multi-Society Task Force on Colorectal Cancer and a guideline from the American Society of Gastrointestinal Endoscopy [1,2].


The adequacy of the bowel preparation has a significant impact on the quality of the colonoscopy, but the prep is inadequate in up to 25 percent of examinations [3,4]. Inadequate bowel preparation may [5,6]:

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Literature review current through: Dec 2017. | This topic last updated: Jan 11, 2018.
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  1. Johnson DA, Barkun AN, Cohen LB, et al. Optimizing adequacy of bowel cleansing for colonoscopy: recommendations from the U.S. multi-society task force on colorectal cancer. Gastrointest Endosc 2014; 80:543.
  2. ASGE Standards of Practice Committee, Saltzman JR, Cash BD, et al. Bowel preparation before colonoscopy. Gastrointest Endosc 2015; 81:781.
  3. Froehlich F, Wietlisbach V, Gonvers JJ, et al. Impact of colonic cleansing on quality and diagnostic yield of colonoscopy: the European Panel of Appropriateness of Gastrointestinal Endoscopy European multicenter study. Gastrointest Endosc 2005; 61:378.
  4. Harewood GC, Sharma VK, de Garmo P. Impact of colonoscopy preparation quality on detection of suspected colonic neoplasia. Gastrointest Endosc 2003; 58:76.
  5. Rex DK, Imperiale TF, Latinovich DR, Bratcher LL. Impact of bowel preparation on efficiency and cost of colonoscopy. Am J Gastroenterol 2002; 97:1696.
  6. Chokshi RV, Hovis CE, Hollander T, et al. Prevalence of missed adenomas in patients with inadequate bowel preparation on screening colonoscopy. Gastrointest Endosc 2012; 75:1197.
  7. Rex DK. Optimal bowel preparation--a practical guide for clinicians. Nat Rev Gastroenterol Hepatol 2014; 11:419.
  8. Borg BB, Gupta NK, Zuckerman GR, et al. Impact of obesity on bowel preparation for colonoscopy. Clin Gastroenterol Hepatol 2009; 7:670.
  9. Hassan C, Fuccio L, Bruno M, et al. A predictive model identifies patients most likely to have inadequate bowel preparation for colonoscopy. Clin Gastroenterol Hepatol 2012; 10:501.
  10. Lebwohl B, Wang TC, Neugut AI. Socioeconomic and other predictors of colonoscopy preparation quality. Dig Dis Sci 2010; 55:2014.
  11. Ness RM, Manam R, Hoen H, Chalasani N. Predictors of inadequate bowel preparation for colonoscopy. Am J Gastroenterol 2001; 96:1797.
  12. Spiegel BM, Talley J, Shekelle P, et al. Development and validation of a novel patient educational booklet to enhance colonoscopy preparation. Am J Gastroenterol 2011; 106:875.
  13. Lichtenstein GR, Cohen LB, Uribarri J. Review article: Bowel preparation for colonoscopy--the importance of adequate hydration. Aliment Pharmacol Ther 2007; 26:633.
  14. Kilgore TW, Abdinoor AA, Szary NM, et al. Bowel preparation with split-dose polyethylene glycol before colonoscopy: a meta-analysis of randomized controlled trials. Gastrointest Endosc 2011; 73:1240.
  15. Gurudu SR, Ramirez FC, Harrison ME, et al. Increased adenoma detection rate with system-wide implementation of a split-dose preparation for colonoscopy. Gastrointest Endosc 2012; 76:603.
  16. Enestvedt BK, Tofani C, Laine LA, et al. 4-Liter split-dose polyethylene glycol is superior to other bowel preparations, based on systematic review and meta-analysis. Clin Gastroenterol Hepatol 2012; 10:1225.
  17. Bucci C, Rotondano G, Hassan C, et al. Optimal bowel cleansing for colonoscopy: split the dose! A series of meta-analyses of controlled studies. Gastrointest Endosc 2014; 80:566.
  18. Horton N, Garber A, Hasson H, et al. Impact of Single- vs. Split-Dose Low-Volume Bowel Preparations on Bowel Movement Kinetics, Patient Inconvenience, and Polyp Detection: A Prospective Trial. Am J Gastroenterol 2016; 111:1330.
  19. Khan MA, Piotrowski Z, Brown MD. Patient acceptance, convenience, and efficacy of single-dose versus split-dose colonoscopy bowel preparation. J Clin Gastroenterol 2010; 44:310.
  20. Unger RZ, Amstutz SP, Seo DH, et al. Willingness to undergo split-dose bowel preparation for colonoscopy and compliance with split-dose instructions. Dig Dis Sci 2010; 55:2030.
  21. American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology 2002; 96:1004.
  22. Matro R, Shnitser A, Spodik M, et al. Efficacy of morning-only compared with split-dose polyethylene glycol electrolyte solution for afternoon colonoscopy: a randomized controlled single-blind study. Am J Gastroenterol 2010; 105:1954.
  23. Park JS, Sohn CI, Hwang SJ, et al. Quality and effect of single dose versus split dose of polyethylene glycol bowel preparation for early-morning colonoscopy. Endoscopy 2007; 39:616.
  24. Varughese S, Kumar AR, George A, Castro FJ. Morning-only one-gallon polyethylene glycol improves bowel cleansing for afternoon colonoscopies: a randomized endoscopist-blinded prospective study. Am J Gastroenterol 2010; 105:2368.
  25. Longcroft-Wheaton G, Bhandari P. Same-day bowel cleansing regimen is superior to a split-dose regimen over 2 days for afternoon colonoscopy: results from a large prospective series. J Clin Gastroenterol 2012; 46:57.
  26. Parra-Blanco A, Nicolas-Perez D, Gimeno-Garcia A, et al. The timing of bowel preparation before colonoscopy determines the quality of cleansing, and is a significant factor contributing to the detection of flat lesions: a randomized study. World J Gastroenterol 2006; 12:6161.
  27. Baudet JS, Castro V, Redondo I. Recurrent ischemic colitis induced by colonoscopy bowel lavage. Am J Gastroenterol 2010; 105:700.
  28. http://secure.medicalletter.org/TML-article-1408b (Accessed on January 18, 2013).
  29. ASGE Technology Committee, Mamula P, Adler DG, et al. Colonoscopy preparation. Gastrointest Endosc 2009; 69:1201.
  30. Sharara AI, El-Halabi MM, Abou Fadel CG, Sarkis FS. Sugar-free menthol candy drops improve the palatability and bowel cleansing effect of polyethylene glycol electrolyte solution. Gastrointest Endosc 2013; 78:886.
  31. Beloosesky Y, Grinblat J, Weiss A, et al. Electrolyte disorders following oral sodium phosphate administration for bowel cleansing in elderly patients. Arch Intern Med 2003; 163:803.
  32. Mahadevan U, Kane S. American gastroenterological association institute medical position statement on the use of gastrointestinal medications in pregnancy. Gastroenterology 2006; 131:278.
  33. Ell C, Fischbach W, Keller R, et al. A randomized, blinded, prospective trial to compare the safety and efficacy of three bowel-cleansing solutions for colonoscopy (HSG-01*). Endoscopy 2003; 35:300.
  34. Rejchrt S, Bures J, Siroký M, et al. A prospective, observational study of colonic mucosal abnormalities associated with orally administered sodium phosphate for colon cleansing before colonoscopy. Gastrointest Endosc 2004; 59:651.
  35. Lawrance IC, Willert RP, Murray K. Bowel cleansing for colonoscopy: prospective randomized assessment of efficacy and of induced mucosal abnormality with three preparation agents. Endoscopy 2011; 43:412.
  36. Granberry MC, White LM, Gardner SF. Exacerbation of congestive heart failure after administration of polyethylene glycol-electrolyte lavage solution. Ann Pharmacother 1995; 29:1232.
  37. Turnage RH, Guice KS, Gannon P, Gross M. The effect of polyethylene glycol gavage on plasma volume. J Surg Res 1994; 57:284.
  38. Gabel A, Müller S. Aspiration: a possible severe complication in colonoscopy preparation of elderly people by orthograde intestine lavage. Digestion 1999; 60:284.
  39. Franga DL, Harris JA. Polyethylene glycol-induced pancreatitis. Gastrointest Endosc 2000; 52:789.
  40. Schröppel B, Segerer S, Keuneke C, et al. Hyponatremic encephalopathy after preparation for colonoscopy. Gastrointest Endosc 2001; 53:527.
  41. Wexner SD, Beck DE, Baron TH, et al. A consensus document on bowel preparation before colonoscopy: prepared by a task force from the American Society of Colon and Rectal Surgeons (ASCRS), the American Society for Gastrointestinal Endoscopy (ASGE), and the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES). Gastrointest Endosc 2006; 63:894.
  42. Lopez Morra HA, Fine SN, Dickstein G. Colonic ischemia with laxative use in young adults. Am J Gastroenterol 2005; 100:2134.
  43. Hsu CW, Imperiale TF. Meta-analysis and cost comparison of polyethylene glycol lavage versus sodium phosphate for colonoscopy preparation. Gastrointest Endosc 1998; 48:276.
  44. Ell C, Fischbach W, Bronisch HJ, et al. Randomized trial of low-volume PEG solution versus standard PEG + electrolytes for bowel cleansing before colonoscopy. Am J Gastroenterol 2008; 103:883.
  45. Bitoun A, Ponchon T, Barthet M, et al. Results of a prospective randomised multicentre controlled trial comparing a new 2-L ascorbic acid plus polyethylene glycol and electrolyte solution vs. sodium phosphate solution in patients undergoing elective colonoscopy. Aliment Pharmacol Ther 2006; 24:1631.
  46. Diab FH, Marshall JB. The palatability of five colonic lavage solutions. Aliment Pharmacol Ther 1996; 10:815.
  47. DiPalma JA, Marshall JB. Comparison of a new sulfate-free polyethylene glycol electrolyte lavage solution versus a standard solution for colonoscopy cleansing. Gastrointest Endosc 1990; 36:285.
  48. Vilien M, Rytkønen M. Golytely preparation for colonoscopy: 1.5 liters is enough for outpatients. Endoscopy 1990; 22:168.
  49. Patel V, Nicar M, Emmett M, et al. Intestinal and renal effects of low-volume phosphate and sulfate cathartic solutions designed for cleansing the colon: pathophysiological studies in five normal subjects. Am J Gastroenterol 2009; 104:953.
  50. Di Palma JA, Rodriguez R, McGowan J, Cleveland Mv. A randomized clinical study evaluating the safety and efficacy of a new, reduced-volume, oral sulfate colon-cleansing preparation for colonoscopy. Am J Gastroenterol 2009; 104:2275.
  51. Rex DK, Di Palma JA, Rodriguez R, et al. A randomized clinical study comparing reduced-volume oral sulfate solution with standard 4-liter sulfate-free electrolyte lavage solution as preparation for colonoscopy. Gastrointest Endosc 2010; 72:328.
  52. Rex DK, DiPalma JA, McGowan J, Cleveland Mv. A comparison of oral sulfate solution with sodium picosulfate: magnesium citrate in split doses as bowel preparation for colonoscopy. Gastrointest Endosc 2014; 80:1113.
  53. Desmeules S, Bergeron MJ, Isenring P. Acute phosphate nephropathy and renal failure. N Engl J Med 2003; 349:1006.
  54. http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm103354.htm (Accessed on May 31, 2011).
  55. Zwas FR, Cirillo NW, el-Serag HB, Eisen RN. Colonic mucosal abnormalities associated with oral sodium phosphate solution. Gastrointest Endosc 1996; 43:463.
  56. http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm103354.htm (Accessed on January 23, 2013).
  57. Heher EC, Thier SO, Rennke H, Humphreys BD. Adverse renal and metabolic effects associated with oral sodium phosphate bowel preparation. Clin J Am Soc Nephrol 2008; 3:1494.
  58. Cohen SM, Wexner SD, Binderow SR, et al. Prospective, randomized, endoscopic-blinded trial comparing precolonoscopy bowel cleansing methods. Dis Colon Rectum 1994; 37:689.
  59. Lieberman DA, Ghormley J, Flora K. Effect of oral sodium phosphate colon preparation on serum electrolytes in patients with normal serum creatinine. Gastrointest Endosc 1996; 43:467.
  60. Huynh T, Vanner S, Paterson W. Safety profile of 5-h oral sodium phosphate regimen for colonoscopy cleansing: lack of clinically significant hypocalcemia or hypovolemia. Am J Gastroenterol 1995; 90:104.
  61. Fine A, Patterson J. Severe hyperphosphatemia following phosphate administration for bowel preparation in patients with renal failure: two cases and a review of the literature. Am J Kidney Dis 1997; 29:103.
  62. Fass R, Do S, Hixson LJ. Fatal hyperphosphatemia following Fleet Phospo-Soda in a patient with colonic ileus. Am J Gastroenterol 1993; 88:929.
  63. Kolts BE, Lyles WE, Achem SR, et al. A comparison of the effectiveness and patient tolerance of oral sodium phosphate, castor oil, and standard electrolyte lavage for colonoscopy or sigmoidoscopy preparation. Am J Gastroenterol 1993; 88:1218.
  64. Henderson JM, Barnett JL, Turgeon DK, et al. Single-day, divided-dose oral sodium phosphate laxative versus intestinal lavage as preparation for colonoscopy: efficacy and patient tolerance. Gastrointest Endosc 1995; 42:238.
  65. Mackey AC, Shaffer D, Prizont R. Seizure associated with the use of visicol for colonoscopy. N Engl J Med 2002; 346:2095; author reply 2095.
  66. Pockros PJ, Foroozan P. Golytely lavage versus a standard colonoscopy preparation. Effect on normal colonic mucosal histology. Gastroenterology 1985; 88:545.
  67. Kastenberg D, Chasen R, Choudhary C, et al. Efficacy and safety of sodium phosphate tablets compared with PEG solution in colon cleansing: two identically designed, randomized, controlled, parallel group, multicenter phase III trials. Gastrointest Endosc 2001; 54:705.
  68. Weir MA, Fleet JL, Vinden C, et al. Hyponatremia and sodium picosulfate bowel preparations in older adults. Am J Gastroenterol 2014; 109:686.
  69. Rahman A, Vanner SJ, Baranchuk A, Hookey LC. Serial monitoring of the physiological effects of the standard Pico-Salax® regimen for colon cleansing in healthy volunteers. Can J Gastroenterol 2012; 26:424.
  70. Katz PO, Rex DK, Epstein M, et al. A dual-action, low-volume bowel cleanser administered the day before colonoscopy: results from the SEE CLEAR II study. Am J Gastroenterol 2013; 108:401.
  71. Rex DK, Katz PO, Bertiger G, et al. Split-dose administration of a dual-action, low-volume bowel cleanser for colonoscopy: the SEE CLEAR I study. Gastrointest Endosc 2013; 78:132.
  72. Flemming JA, Vanner SJ, Hookey LC. Split-dose picosulfate, magnesium oxide, and citric acid solution markedly enhances colon cleansing before colonoscopy: a randomized, controlled trial. Gastrointest Endosc 2012; 75:537.
  73. Kontani M, Hara A, Ohta S, Ikeda T. Hypermagnesemia induced by massive cathartic ingestion in an elderly woman without pre-existing renal dysfunction. Intern Med 2005; 44:448.
  74. Schelling JR. Fatal hypermagnesemia. Clin Nephrol 2000; 53:61.
  75. Golzarian J, Scott HW Jr, Richards WO. Hypermagnesemia-induced paralytic ileus. Dig Dis Sci 1994; 39:1138.
  76. Berkelhammer C, Ekambaram A, Silva RG. Low-volume oral colonoscopy bowel preparation: sodium phosphate and magnesium citrate. Gastrointest Endosc 2002; 56:89.
  77. Chen CC, Ng WW, Chang FY, Lee SD. Magnesium citrate-bisacodyl regimen proves better than castor oil for colonoscopic preparation. J Gastroenterol Hepatol 1999; 14:1219.
  78. McKenna T, Macgill A, Porat G, Friedenberg FK. Colonoscopy preparation: polyethylene glycol with Gatorade is as safe and efficacious as four liters of polyethylene glycol with balanced electrolytes. Dig Dis Sci 2012; 57:3098.
  79. Samarasena JB, Muthusamy VR, Jamal MM. Split-dosed MiraLAX/Gatorade is an effective, safe, and tolerable option for bowel preparation in low-risk patients: a randomized controlled study. Am J Gastroenterol 2012; 107:1036.
  80. Matro R, Daskalakis C, Negoianu D, et al. Randomised clinical trial: Polyethylene glycol 3350 with sports drink vs. polyethylene glycol with electrolyte solution as purgatives for colonoscopy--the incidence of hyponatraemia. Aliment Pharmacol Ther 2014; 40:610.
  81. Bigard MA, Gaucher P, Lassalle C. Fatal colonic explosion during colonoscopic polypectomy. Gastroenterology 1979; 77:1307.
  82. Hjelkrem M, Stengel J, Liu M, et al. MiraLAX is not as effective as GoLytely in bowel cleansing before screening colonoscopies. Clin Gastroenterol Hepatol 2011; 9:326.
  83. Siddique S, Lopez KT, Hinds AM, et al. Miralax with gatorade for bowel preparation: a meta-analysis of randomized controlled trials. Am J Gastroenterol 2014; 109:1566.
  84. Enestvedt BK, Brian Fennerty M, Zaman A, Eisen GM. MiraLAX vs. Golytely: is there a significant difference in the adenoma detection rate? Aliment Pharmacol Ther 2011; 34:775.
  85. Brown AR, DiPalma JA. Bowel preparation for gastrointestinal procedures. Curr Gastroenterol Rep 2004; 6:395.
  86. Ori Y, Rozen-Zvi B, Chagnac A, et al. Fatalities and severe metabolic disorders associated with the use of sodium phosphate enemas: a single center's experience. Arch Intern Med 2012; 172:263.
  87. Mendoza J, Legido J, Rubio S, Gisbert JP. Systematic review: the adverse effects of sodium phosphate enema. Aliment Pharmacol Ther 2007; 26:9.
  88. Sharma VK, Chockalingham S, Clark V, et al. Randomized, controlled comparison of two forms of preparation for screening flexible sigmoidoscopy. Am J Gastroenterol 1997; 92:809.
  89. Sajid MS, Caswell JF, Abbas MA, et al. Improving the view during flexible sigmoidoscopy: a systematic review of published randomized, controlled trials comparing the use of oral bowel preparation versus enema bowel preparation. Updates Surg 2015; 67:247.
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