Systematic review: adverse event reports for oral sodium phosphate and polyethylene glycol

Background Screening colonoscopy exposes healthy patients to the risk of serious adverse events associated with bowel preparation. Randomized controlled trials are not an effective method for evaluating this risk. Aim To search published literature in order to characterize the risk of adverse events associated with oral polyethylene glycol (PEG) or sodium phosphate (NaP). Methods A systematic review identified case reports of any serious events associated with PEG or NaP. Reports to the Food and Drug Administration (FDA) were also examined. Results Fifty-eight publications of significant events in 109 patients using NaP and 22 patients using PEG were identified. As the total number of prescriptions issued is unknown, rates for the two agents cannot be directly compared. Most commonly reported were electrolyte disturbances, renal failure and colonic ulceration for NaP and Mallory-Weiss tear, electrolyte disturbances and allergic reactions for PEG between January 2006 and December 2007; there were 171 cases of renal failure reported to the FDA following use of NaP and 10 following PEG. Conclusions Adverse events following bowel preparation are uncommon, but potentially serious. Given that many of these patients are healthy individuals undergoing screening, the benefit/risk ratio must be carefully considered when deciding which preparation to prescribe in individual patients.