Earlier this year, the American College of Gastroenterology revised its colorectal cancer screening guidelines for the first time in eight years, and one of the most noticeable changes was its recommendation to split the dose of bowel preps.
The new guideline goes against years of practice for gastroenterologists, many of whom have yet to adopt the new “split dosing” guidelines. In years past, doctors had patients take all of the bowel preparation prescription the day before the colonoscopy.
“This effectively cleaned out the fecal debris, but left the potential for a different problem that can develop when the time between the end of the preparation process and the start of the colonoscopy is prolonged,” Douglas K. Rex, MD, a past president of ACG, and lead author of the new guidelines, wrote in a February Q&A with The New York Times. “Thick mucus and intestinal secretions empty out of the small intestine during that interval and stick to the first parts of the colon.”
In the new guidelines, the ACG said the best established principle to enhance the effectiveness of bowel preps is “splitting” the dose. This is when patients take half of the bowel prep prescription the night before the colonoscopy, and the other half the day of the procedure.
“When all of the bowel preparation is given on the day before examination and the interval between the last dose of preparation and the performance of colonoscopy is prolonged, the probability of poor preparation increased dramatically, particularly in the cecum and ascending colon,” the ACG wrote in the guidelines, which first appeared in the March 2009 issue of the American Journal of Gastroenterology.
The guidelines said that split dosing can be carried out with oral dosing of polyethylene glycol or sodium phosphate preparation. In addition, patients can ingest clear liquids until two hours before sedation, according to guidelines released by the American Society of Anesthesiologists.
“Recent guidelines for an effective and safe preparation are available, and have particularly emphasized the importance of aggressive hydration before and during the preparation, during the procedure, and after the procedure, especially when using oral sodium phosphate preparations,” according to the ACG guidelines.