Studying bowel prep for capsule endoscopy

Aug. 15, 2020

The diagnostic yield for capsule endoscopy can be hindered by the presence of dark intestinal fluid or air bubbles or both, which limit the visualization of the mucosa and any abnormalities within the small bowel. In guidelines published in the journal Gastroenterology, the use of bowel preparation for capsule endoscopy is strongly recommended, but it is acknowledged that there is only low-quality evidence for the efficacy of bowel preparations to support this statement.

In a prospective randomized controlled study published in Gastroenterology Report, a team of researchers at Mayo Clinic investigated the use of a comprehensive combined purgative preparation with right lateral position to determine if this approach would improve visualization, diagnostic yield and completion rates without compromising patient safety or satisfaction.

"Our study is unique in the combination of medications used with the addition of patient positioning after ingesting the capsule," said Stephanie L. Hansel, M.D., M.S.


Patients were randomized to one of two arms of the study. Patients in one arm completed our standard fasting preparation, which included ingesting no solid food after 7 p.m. the evening prior to the procedure and no liquids four hours prior to the procedure.

Patients in a second arm of the study completed a bowel preparation of 2 L of polyethylene glycol starting at 7 p.m. the evening prior to the procedure. They also ingested 5 mL of simethicone and 5 mg of metoclopramide (liquid preparation) 20 minutes prior to swallowing the capsule endoscopy. Additionally, following capsule ingestion, they lay in the right lateral position for 30 minutes.

All patients completed a questionnaire prior to leaving the procedural area.


The study found the comprehensive combined bowel preparation did not significantly improve small bowel visualization or the diagnostic yield of the procedure. The completion rate of capsule endoscopy did improve in patients with bowel preparation. Interestingly, the use of bowel preparation significantly increased patient discomfort. There were no adverse events reported in the study.

"Based on our study and other evidence in the literature, we do not recommend bowel preparation for all patients undergoing capsule endoscopy," said Elizabeth Rajan, M.D. "We acknowledge there may be select patient populations that may benefit from bowel preparation prior to capsule endoscopy, but there is insufficient data to recommend a specific type of bowel preparation."

For more information

Enns RA, et al. Clinical practice guidelines for the use of video capsule endoscopy. Gastroenterology. 2017;152:497.

Hansel SL, et al. Evaluating a combined bowel preparation for small-bowel capsule endoscopy: A prospective randomized–controlled study. Gastroenterology Report. 2020;8:31.