Researchers consider new options in colonoscopy prep products

A new study presented at the American College of Gastroenterology’s 74th Annual Scientific Meeting in San Diego, Calif., places new emphasis on the importance of adequate bowel preparation prior to colonoscopies. The news comes as clinicians are evaluating new bowel preparation solutions to replace popular ones that were pulled from the market or given a black box warning by the Food and Drug Administration (FDA).

The study performed at the VA Medical Center in Phoenix, Ariz., cites inadequate bowel preparation by the patient prior to colonoscopies as resulting in earlier follow-up colonoscopies than when adequate cleansing is performed.

“Endoscopists’ ability to detect colonic legions, especially the flat or depressed ones, is greatly linked to the quality of bowel preparation. For years, we have emphasized the importance of adequate bowel preparation for patients to help ensure the detection of adenomas during colonoscopy, especially on the right side of the colon,” explains Dr. Veronika Karasek. “This new finding suggests that endoscopists are taking into consideration the quality of preparation when recommending a follow-up interval, regardless of the findings of the examination.”

As gastroenterologists consider the importance of bowel preparation, they are also evaluating new formulations of bowel preparation products for their patients. In December 2008, the FDA issued a black box warning on prescription brands of a type of laxative known as oral sodium phosphates, or OSPs. Fleet, maker of a popular over-the-counter brand of OSP, also pulled its products from shelves. OSPs were linked to a serious type of kidney injury known as acute phosphate nephropathy.

During the seminars, researchers at the American College of Gastroenterology presented papers evaluating new bowel preparation formulations and approaches.

In a pilot study led by Dr. Ron Palmon at the Mt. Sinai School of Medicine, researchers evaluated the safety and efficacy of Polyethelne Glycol (PEG) plus ascorbic acid (Moviprep) compared to magnesium citrate for bowel preparation before colonoscopy. The randomized study included 90 patients and found that overall colon preparation was excellent or good for 92 percent of those receiving the PEG and ascorbic acid solution, as well as 86 percent of those receiving the magnesium citrate formulation. Sixty-two percent of the patients given the PEG and ascorbic acid formulation indicated that it was easy to fairly easy to take, compared to 82 percent of those given the magnesium citrate formulation.

The study also showed a significant improvement in the quality of bowel preparation when using split dosing with either preparation. Split-dosing involves doses given both the night before a procedure and a few hours prior – versus traditional dosing, given the day before.

“Both PEG with ascorbic acid and magnesium citrate provided good to excellent colon cleansing in almost all the patients we evaluated,” explained Dr. Palmon. “The fact that patients were, for the most part, able to tolerate these products and found them relatively easy to administer suggests that they may be an alternative to phosphosoda. Regardless of which formulation a clinician chooses to recommend, we must all reinforce how vital proper procedure preparation is to colonoscopy.”