Last year, a Medical Letter article reviewing colonoscopy preparations warned that oral sodium phosphate preparations, such as Fleet Phospho-Soda solution and Visicol tablets, could cause significant electrolyte disturbances and, rarely, renal failure (Med Lett Drugs Ther 2005; 47:53). A subsequent report documented acute phosphate nephropathy and renal failure in 21 patients who had used sodium phosphate before colonoscopy (GS Markowitz et al. J Am Soc Nephrol 2005; 16:3389). Seventeen of these patients were women and 14 were taking an angiotensin-converting enzyme (ACE) inhibitor or...

MoviPrep (Salix) is a new polyethylene glycol (PEG)-based bowel cleansing preparation approved for use in adults prior to colonoscopy. It contains ascorbic acid, which acts as an additional cathartic and flavoring agent, and requires a lower volume of fluid (3 L compared to the traditional 4 L) than most other PEG products. HalfLytely is an FDA-approved 2-L PEG product, but it must be taken with bisacodyl.