The Hospice Clinician Blog

This month in Archives of Internal Medicine, a group of investigators reported on their experience with severe complications of sodium phosphate (Fleet®) enemas.

The potential renal toxicity of oral sodium phosphate solutions, previously used for bowel cleansing prior to colonoscopy, has been well described. Major concerns began with a paper published in the November 2005 issue of the Journal of the American Society of Nephrology, which described 21 cases of acute renal failure, all of which were directly attributable to ingestion of oral sodium phosphate solutions. Further research linked many more cases of renal failure to the use of sodium phosphate solutions for bowel prep, some of which resulted in permanent impairment of renal function severe enough to require long-term dialysis. The condition was given the name “acute phosphate nephropathy”, or APhN.

In December 2008, following continuing reports of APhN, the FDA issued an alert stating that over-the-counter oral sodium phosphate solutions should no longer be used for bowel cleansing. Shortly thereafter, Fleet Phosphosoda was voluntarily withdrawn from the US market. Sodium phosphate tablets (brand names OsmoPrep and Visicol) remain on the market but were given a boxed warning regarding the risk for acute kidney injury potentially resulting in permanent renal function impairment.

Potential risk factors for renal injury from oral sodium phosphate include:

• increased age
• female gender
• baseline kidney disease
• inadequate hydration or hypovolemia
• increased bowel transit time
• use of ACE inhibitors, ARBs, diuretics or NSAIDs

Fleet enemas have remained available over-the-counter, and are commonly used in hospice for the treatment of constipation. Now, a group of researchers from Israel has published a study indicating that sodium phosphate enemas may also be associated with acute renal failure. Yaacov Ori and colleagues conducted a retrospective case series of 11 elderly patients who received a Fleet enema for constipation and developed acute renal failure. Most presented within 24 hours with hypotension and volume depletion, extreme hyperphosphatemia, and severe hypocalcemia. Hypernatremia and hypokalemia were seen in most patients. Two patients required urgent hemodialysis and five patients died. One patient was autopsied and calcium-phosphate deposition was found within the renal tubular lumen (consistent with APhN). The authors concluded that sodium phosphate enemas may, like the oral solution and tablets, lead to severe metabolic disorders and acute kidney injury.

In hospice, we often use Fleet enemas to relieve constipation that is unrelieved by other means. Perhaps we should use Fleet enemas with more caution. The vast marjority of our patients are of advanced age, and most have one or more other risk factors from the list above—in other words, almost ALL would be considered high-risk.

What do you think? Granted, this is a small-scale observational study, but should it cause us to think twice when prescribing a Fleet enema?

Reference: Ori Y, Rozen-Zvi B, Chagnac A, et al. Fatalities and severe metabolic disorders associated with the use of sodium phosphate enemas: a single center’s experience. Arch Intern Med 2012; 172: 263-265.