Oral Sodium Phosphate Kidney Injury Warning Issued in Canada

Health Canada has issued a warning about side effects of oral sodium phosphate products, such as Fleet Phospho-soda, as they could cause electrolyte disturbances and kidney injury when used as a bowel cleanser at high doses.

The drug regulatory agency in Canada issued a statement on March 5, 2009, warning that Canadians should not use these oral sodium phosphate products for bowel prep unless they are specifically recommended by their doctor in an individual case.

Although the products appear to be safe when used at lower doses as a laxative, when used to cleanse the bowels as part of colonoscopy prep or before other medical procedures, oral sodium phosphate side effects could a serious kidney injury known as acute phosphate nephropathy. This could result in renal failure, the need for dialysis treatment, a kidney transplant or death.

In Canada, there are three authorized oral sodium phosphate products that are labeled for laxative use and as a bowel cleanser, Phoslax, Fleet Phospho-soda Oral Laxative and Phosphate Solution, which is sold as Pharmasave Phosphates Solution, Option + Phosphates Solution and Reserve Phosphates Solution.

Health Canada reports that they have received reports of at least 53 oral sodium phosphate adverse reactions, with 30 of them involving kidney problems and 27 of those reported as serious. Allergic reactions, gastrointestinal symptoms, neurological and cardiovascular problems were also reported as other adverse effects.

In the United States, the FDA issued a warning about the risk of kidney injury from oral sodium phosphate products in December 2008, and required that two prescription products add a “black box” warning about the risk of acute phosphate nephropathy, which is the strongest warning that can be placed on a prescription product.

In a statement released by the FDA on December 11, 2008, the U.S. drug regulators also indicated that over-the-counter oral sodium phosphate products, such as Fleet Phospho-soda, should not be used as a bowel prep due to the potential side effects.

The same day the FDA warned about the risk of kidney problems, a Fleet Phospho-soda recall was issued and the manufacturer, C.B. Fleet, indicated that they will stop selling the product as an over-the-counter laxative, but may seek approval to market the product as a prescription drug.

Since 2004, nearly 200 Fleet Phospho-soda lawsuits have been filed in the United States in various state and federal courts alleging that the manufacturer failed to warn that using high doses of the over-the-counter laxative as a bowel prep for colonoscopies could lead to potentially life-threatening kidney injury.