DIA Daily reports that on Thursday, December 11, 2008, the Food and Drug Administration (FDA) stated that it “will add the sternest safety warnings available” — the so-called black-box warning — “to prescription drugs used to cleanse the bowel before colonoscopies.” The FDA was spurred into action after it “received more than 20 reports of a rare, but serious form of kidney failure among patients taking the drugs, known as oral phosphate products.” Therefore, Salix Pharmaceuticals’ Visicol (sodium phosphate monobasic monohydrate, sodium phosphate dibasic anhydrous ) and OsmoPrep (sodium biphosphate, sodium phosphate) will now include a label that “warns that the drugs should be used with caution in older patients, those that suffer from dehydration and kidney disease, or those that take medications that affect the kidneys.”

Oral sodium phosphate drugs, “sold with and without a prescription, have been associated with acute phosphate nephropathy, the kidney injury,” and it “may lead to permanent kidney damage,” Bloomberg News (12/12, Blum) adds. According to Joyce Korvick, M.D., deputy director of the agency’s Division of Gastroenterology Products at the Center for Drug Evaluation and Research, “one reason for the risk might be that some people may be dehydrated and not drinking enough fluid when they use oral sodium phosphate products for bowel cleansing, despite the instructions on the products,” WebMD (12/11, Hitti) reported. Meanwhile, the FDA is also recommending “that consumers not use over-the-counter oral sodium phosphate products, such as Fleet Phospho-soda, for bowel cleansing.”

Those “treatments also shouldn’t be used for bowel cleansing, and will get new warnings” as well, HealthDay (12/11, Reinberg) added. “At lower doses, however, they are safe for use as laxatives, the FDA said.” But there “are alternatives to these preparations that can be used for bowel cleansing, including GoLYTELY and HalfLytely Bowel Prep,” Dr. Korvick pointed out. Meanwhile, Hemant K. Roy, M.D., of Evanston-Northwestern Healthcare in Illinois, who wrote an editorial in the Archives of Internal Medicine that accompanied a study on “the risks of oral sodium phosphate” solutions, “stressed that warranted concerns about phosphate solutions shouldn’t keep patients from undergoing colon cancer screening.” The (NC) Triangle Business Journal (12/11, Coletta) and MedPage Today (12/11, Gever) also covered the story, as did the Los Angeles Times (12/11, Maugh) in its Booster Shots blog.

Drugmaker recalls over-the-counter bowel cleansing solutions. In a separate article, Bloomberg News (12/12, Pollack, Blum) reports that “C.B. Fleet Co., a closely held maker of laxative products, said it was voluntarily withdrawing its oral, over-the-counter bowel cleansing solutions after U.S. health regulators warned such drugs may harm the kidneys.” Specifically, the drugmakers are recalling “Fleet Phospho-soda and Fleet Phospho-soda EZ-Prep Bowel Cleansing System used to clear the bowels before a colonoscopy,” a “decision [that] was made because the Food and Drug Administration said…that this class of drugs should be available only by prescription.”