The FDA has approved an oral tablet formulation of sodium sulfate, magnesium sulfate, and potassium chloride (Sutab – Braintree) for colon cleansing prior to colonoscopy in adults. A sodium sulfate-based oral solution (Suprep) has been available in the US since 2010. Sutab is the second tablet formulation to be approved for bowel cleansing prior to colonoscopy; a sodium phosphate-based tablet (OsmoPrep) was approved earlier.

The FDA has approved Plenvu (Salix), a polyethylene glycol (PEG)-containing oral powder for reconstitution, for colon cleansing prior to colonoscopy in adults. Plenvu is the first PEG-containing colonoscopy preparation that requires only 1 L of water for dissolution and ingestion of 1 L of clear fluid in addition.

The FDA has approved Clenpiq (Ferring), a low-volume oral solution that contains sodium picosulfate, magnesium oxide, and anhydrous citric acid, for colon cleansing prior to colonoscopy in adults. The ready-to-drink solution contains the same ingredients as Prepopik, which is supplied as a powder for reconstitution.

Colonoscopy remains the preferred method of colorectal cancer screening. Many patients consider cleansing the bowel in preparation for colonoscopy the most unpleasant part of the procedure, but inadequate bowel preparation significantly lowers the diagnostic yield.

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 angiotensin receptor blocker (ARB). The FDA recently issued an alert advising against use of oral sodium phosphate in patients with kidney disease or uncorrected electrolyte abnormalities and urges caution in patients taking drugs that may affect renal function such as diuretics, NSAIDs, ACE inhibitors or ARBs.

Since the publication of our article on colonoscopy preparations,1 which compared polyethylene glycol electrolyte solutions (GoLytely, and others) with sodium phosphate (Fleet Phospho-Soda, and others), some readers have told us that we should have included a combination of a magnesium citrate solution with bisacodyl tablets (Evac-QKwik, and others) as an alternative. In one study, such a preparation offered better cleansing and patient tolerance than a sodium phosphate regimen.2

1. Colonoscopy preparations. Med Lett Drugs Ther 2005; 47:53.

2. M Delegge and R Kaplan. Efficacy of bowel preparation with the use of a prepackaged, low fibre diet with a low sodium, magnesium citrate cathartic vs. a clear liquid diet with a standard sodium phosphate cathartic. Aliment Pharmacol Ther 2005; 21:1491.

Many patients consider cleansing the bowel in preparation for colonoscopy the most unpleasant part of the procedure. Several methods are available.