FDA: Oral Sodium Phosphates Not Safe For Double Dose

Bellevue, WAThey are two things that many people might not think go together: the use of an oral sodium phosphate and an increased risk of kidney failure. However, according to warnings released by the US Food and Drug Administration (FDA), the risk of OSP kidney damage is high enough that the products' uses have been revised. Unfortunately, there could be many people out there who suffered kidney damaged linked to the use of an oral sodium phosphate but did not realize it.

The problem is not necessarily with the oral sodium phosphates themselves—they are still considered safe when used at low doses. The problem is reportedly when they are used for bowel cleansing prior to a colonoscopy. When they are used as purgatives to clean the patient's bowel, the oral sodium phosphates could cause kidney failure. Using the oral sodium phosphates as a purgative means taking two doses rather than one. That extra dose appears to be the difference.

Injuries reportedly associated with the use of oral sodium phosphates include kidney dysfunction, gastrointestinal symptoms, allergic reactions and cardiovascular and neurological problems.

Both the US FDA and Health Canada have announced changes to the labeling of oral sodium phosphates. According to a ctv.ca news report (August 5, 2009), Health Canada has announced that oral sodium phosphates should be used on a single-dose basis. Additionally, Fleet Phospho-Soda Oral Laxative has been discontinued in Canada. Other products are still available but will be relabeled.

Meanwhile, the FDA issued black box warnings regarding the risks of oral sodium phosphates. Similar to Canada, Fleet Phospho-Soda was withdrawn from the US market after the FDA's announcement was made.

Although the FDA's announcement was made in 2008, it appears there has been at least some awareness of the risks of kidney failure in patients who use double doses of oral sodium phosphates. An August 16, 2007, article at abcmoney.co.uk reports about lawsuits filed against the maker of Fleet Phospho-soda and says that at least 50 such lawsuits were filed. The lawsuits alleged that patients suffered harm, including kidney failure, after the use of Fleet Phospho-soda prior to medical procedures.

According to the article, Phospho-soda was on the market for over a century but it was only in the early 1990s that it was promoted to cleanse the bowels prior to colonoscopies. However, the article notes, the FDA did not certify this new use and even sent an alert in May, 2006, about 21 documented cases of kidney failure linked to oral sodium phosphates.