"For bowel cleansing before colonoscopy, a new two liter solution of polyethylene glycol (PEG) plus ascorbic acid is as effective as the standard four liter PEG plus electrolytes solution, and is more acceptable to patients, researchers report in the
American Journal of Gastroenterology for April.
The addition of ascorbic acid appears not only to improve the taste of the gut lavage solution, it also reduces the effective volume of solution needed for adequate cleansing, Dr. Christian Ell, from Dr. Horst Schmidt Kliniken, Wiesbaden, Germany and colleagues explain.
"The cathartic effects of ascorbic acid are thought to be due to its absorption mechanism, which becomes saturated at high doses. Excess ascorbic acid, which cannot be absorbed, remains in the bowel where it exerts an osmotic effect, acting synergistically with PEG," they note.
In a randomized study, Dr. Ell and colleagues tested the safety, efficacy and patient acceptability of the two liter PEG with ascorbic acid solution (PEG+Asc; Moviprep, Norgine, Harefield UK) with that of the standard four liter PEG with electrolytes solution (PEG+E; Klean-Prep, Norgine) for bowel cleansing before colonoscopy. Both groups used a split-dose regimen, ie, taking half of the solution the evening before the colonoscopy and the other half early in the morning of the procedure.
Successful gut cleansing was achieved in 136 of 153 patients (88.9 per cent) who used the two L PEG+Asc solution and 147 of 155 patients (94.8 per cent) who used the four L PEG+E solution. The difference fell within the predefined limit for noninferiority, note the researchers.
Patients who drank the two L PEG+Asc solution reported significantly less nausea and abdominal pain than those who drank the standard four L solution.
"Patients were also asked about the acceptability and taste of the cleansing agent and rated the two L PEG+Asc solution significantly better than the four L PEG solution on both counts," the investigators report. Therefore, the two L solution "may be associated with improved treatment adherence," Dr. Ell and colleagues conclude.
Am J Gastroenterol 2008;103:883-893"
