Box Warning and Recall for Bowel PrepsDec 12, 2008 | Parker Waichman LLP The U.S. Food and Drug Administration (FDA) just announced it is adding a Boxed Warning to the prescription oral sodium phosphate (OSP) products Visicol and OsmoPrep to warn consumers about the risk of acute phosphate nephropathy, which is a type of serious kidney injury. OSPs are generally taken by patients for bowel cleansing prior to certain medical procedures such as colonoscopy.
The FDA has also mandated that the OSP maker develop a risk evaluation and mitigation strategy (REMS), distribute a Medication Guide to alert patients to the risk of acute kidney injury associated with the use of OSPs, and conduct a post-marketing clinical trial to further assess the risk of acute kidney injury with OSP use.
The FDA is also concerned with the risks of using over-the-counter (OTC) OSP products such as Fleet Phospho-soda, when taken at higher doses for bowel cleansing. Current information does not indicate a risk of acute kidney injury when OTC OSPs are used at lower, laxative-level doses; however, when used for bowel cleansing, the OTC OSPs present the same kidney risks as prescription strength OSPs. Because of this and also because of ongoing reports of acute phosphate nephropathy, the FDA plans to update labeling for the OTC products. The agency recommends consumers not use OTC OSPs for bowel cleansing.
“Though rare, these are serious adverse events associated with the use of oral sodium phosphates—both prescription and over-the-counter products,” said Janet Woodcock, M.D., director of the FDA’s Center for Drug Evaluation and Research. Woodcock added, “In some cases, these serious adverse events occurred in patients with no pre-existing health factors that would have put them at risk for developing kidney injury. We cannot rule out, however, that some of these patients were dehydrated prior to ingestion of OSP products or they did not drink sufficient fluids after ingesting OSP products.”
In 2006, the FDA issued a “Science Paper and a Healthcare Professional” sheet describing the risks associated with the use of OSP products for bowel cleansing. As part of the FDA’s post-marketing surveillance, it has received 20 reports of kidney injury linked to OsmoPrep; three were biopsy-proven cases of acute phosphate nephropathy. The onset of kidney injury varied, with some occurring within several hours and others within 21 days after using the OSP.
The FDA warns that OSPs should never be used by children under 18 years of age or with other laxative products containing sodium phosphate and is recommending caution for bowel cleansing by people over 55 years of age; who suffer from dehydration, kidney disease, acute colitis, or delayed bowel emptying; and people taking certain medicines that affect kidney function, such as diuretics (fluid pills), angiotensin converting enzyme inhibitors (blood pressure lowering medications), angiotensin receptor blockers (for treatment of high blood pressure, heart, or kidney failure), and, possibly, nonsteroidal, anti-inflammatory drugs (such as ibuprofen and other arthritis medications).
Meanwhile, in response to the FDA warning, C.B. Fleet Company immediately announced a voluntary recall—directed to retailers and wholesalers—of its OTC products: Fleet(R) Phospho-soda(R) and Fleet(R) Phospho-soda(R) EZ-Prep(R) Bowel Cleansing System. Fleet will look to address the FDA decision to make these products available by prescription only.