FDA Requires Black Box Warning on Oral Sodium Phosphate Products (OSP)
December 12, 2008
After receiving reports linking oral sodium phosphate products (OSP) to kidney injuries, the U.S. Food and Drug Administration (FDA) mandated that its manufacturer, Salix Pharmaceuticals Ltd, add a Boxed Warning to the prescription drugs Visicol and OsmoPrep. Additionally, the FDA expressed concern about the use of related over-the-counter (OTC) laxatives (e.g., Fleet Phospho-soda). OSPs are commonly used by patients preparing to undergo a colonoscopy (colon examination to detect precancerous growths) because OSP products cleanse the bowels.
The FDA is concerned about the risk of acute phosphate nephropathy, a type of kidney injury. OSP laxatives can lead to dehydration and increased levels of phosphate in the kidneys which cause an overproduction of crystals that can damage the organs.
In 2006, the FDA issued a Science Paper outlining the potential risks stemming from OSP products for bowel cleansing. Since that time, it has received 20 reports of kidney damage from patients who used OsmoPrep. Of those cases, three were biopsy-proven cases of acute phosphate nephropathy. The time in which patients became symptomatic varied. For some, the onset of injury occurred within several hours of ingestion, but in other cases the effects manifested up to 21 days after use. Patients over the age of 55 and those with pre-existing kidney problems are at special risk.
In addition to the warning labels, the FDA is requiring the manufacturer of OSP products to take further measures, including the development of a risk evaluation and mitigation strategy (REMS). Drug makers will also be required to distribute a Medication Guide alerting patients of the potential risk, and to conduct post-marketing clinical trials to better determine the risk associated with OSP use. The FDA has also issued a recommendation that consumers not use OTC OSP laxatives for bowel cleansing. Additionally, OSP products should not be used in conjunction with other laxative products containing sodium phosphate or by children under 18 years of age.
Because OSP products are not intended for long term use, patients that may have used them once may sustain kidney impairment. For instance, if a patient uses Visicol or OsmoPrep in preparation for certain medical procedures such as a colonoscopy, using the drug just that one time could potentially cause kidney damage.
If you or a loved one suffered kidney damage caused by an OSP product, contact us today for a confidential and free case evaluation.