New Guidelines Issued on Bowel Prep for Colonoscopy

Larry Hand

October 08, 2014

With up to 25% of all colonoscopies reported as having an inadequate bowel preparation, the US Multi-Society Task Force on Colorectal Cancer has published new consensus guidelines aimed at raising the preparation compliance goal to at least 85%.

Inadequate bowel preparation has serious consequences, including lower adenoma detection, longer procedural time, and shorter intervals between examinations, the task force writes in an article published in the October issue of Gastroenterology.

David A. Johnson, MD, head of gastroenterology at the Eastern Virginia Medical School, Norfolk, and colleagues conducted a systematic review of medical literature published between January 1980 and August 2013, as well as published articles and abstracts presented at national meetings. They chose 1980 as the first year because that was when the US Food and Drug Administration (FDA) approved the polyethylene glycol–electrolyte lavage solution–based preparation.

The new task force guidelines have been vetted and approved by the American College of Gastroenterology, American Gastroenterological Society, and American Society of Gastrointestinal Endoscopy governing boards.

"Ineffective bowel cleansing for colonoscopy results in missed precancerous lesions and increased costs related to early repeat procedures," Dr Johnson and colleagues write. "Efficacy and tolerability of bowel preparations are important and related goals, but efficacy is of primary importance because of the substantial consequences of inadequate cleansing."

The guidelines cover several areas, including:

Adequate Preparation

  • Preparation should be sufficient to allow polyp detection greater than 5 mm.

  • If deemed inadequate during colonoscopy, examination should be repeated with a more aggressive preparation regimen within 1 year.

  • If deemed adequate, follow guidelines for screening.

Dosing and Timing

  • Use a split-dose cleansing agent.

  • A same-day regimen is acceptable for split-dose, especially for afternoon procedures.

  • The second dose should begin 4 to 6 hours before the procedure begins.

Diet During Cleansing

  • Either low-residue or full liquids until the evening before procedure.

Patient Education

  • Provide patients with oral and written instructions.

  • Ensure appropriate support is in place.

Quality of Preparation

  • Assess adequacy after all appropriate efforts to clear residual debris.

  • Measure rate of adequacy routinely.

  • Achieve adequate cleansing in at least 85% of examinations per physician.

FDA-Approved Preparations

  • Consider the patient's medical history, medications, and prior procedures when selecting approved regimens.

  • Use a split-dose regimen of 4 L polyethylene glycol–electrolyte lavage solution.

Over-the-Counter Preparations

  • Regardless of agent, use a split-dose regimen.

  • Use caution for certain populations, such as patients with chronic kidney disease.


  • Routine use of adjunctive agents is not recommended.

Patient Preference/Willingness

  • Split-dose is associated with greater willingness compared with day-before regimen.

  • Low-volume agents are associated with greater willingness to undergo a repeat procedure.

Specific Populations

  • Insufficient evidence to recommend specific preparation regimens for elderly, children, and adolescents.

  • Sodium phosphate (NaP) preparations are not recommended in children younger than 12 years or with risk factors for medication complications.

  • Avoid NaP use in patients with known or suspected inflammatory bowel disease.

  • Consider using additional bowel purgatives in patients with risk factors for inadequate preparation.

  • Use low-volume or extended-time delivery in patients after bariatric surgery.

  • Direct pregnant women to use tap water enemas.

  • Insufficient evidence to recommend specific regimens in patients with a history of spinal cord injury.

Salvage Options

  • Large-volume enemas can be used for patients presenting with brown effluent despite complying with preparation regimen.

  • Through-the-scope enema can be considered especially for patients who receive propofol sedation.

This research was supported in part by the Veterans Health Administration. Seven authors have reported financial relationships with a number of companies; the other authors have disclosed no relevant financial relationships.

Gastroenterology. 2014;147:903-924. Full text


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