Bowel preparations for colonoscopy: a review.

PURPOSE: The mechanisms of action, clinical efficacy, tolerability, and safety of two major classes of bowel purgatives, poly-ethylene glycol- electrolyte lavage solutions (PEG-ELSs) and sodium phosphate preparations, are reviewed.
SUMMARY: PEG-ELSs are osmotically balanced preparations that promote bowel cleansing through the ingestion of nonabsorbable fluid. Sodium phosphate preparations are hyperosmotic purgatives that promote bowel cleansing by osmotically drawing fluid into the bowel lumen for evacuation. Studies suggest that 2-L PEG-ELS regimens are generally as effective as and more tolerable than full-volume PEG-ELS preparations. Studies have also found that sodium phosphate tablets may provide a more tolerable alternative to PEG-ELS regimens and traditional sodium phosphate products without compromising bowel cleansing efficacy. Proper renal function plays a particularly important role in avoiding potential safety issues related to sodium phosphate-induced shifts in the fluid and electrolyte balance. Preventing dehydration in patients undergoing bowel preparation can prevent severe adverse events, regardless of the purgative administered. Optimizing the process of bowel preparation involves administering proper purgative choices in appropriate patient populations. Moreover, patient education and compliance with preparation instructions, including correct dosing and adequate hydration, may reduce the risk of adverse events and serious complications.
CONCLUSION: Although next-generation PEG-ELS and sodium phosphate products are well tolerated and preferred by patients over traditional bowel preparation regimens, safety issues remain a concern for both purgative classes. Sodium phosphate preparations are generally more effective and better tolerated than PEG-ELS formulations but should be administered with caution in patients with preexisting or at an increased risk for electrolyte disturbances.