Severe kidney injury linked to use of OSP products
July 18th, 2009 by Jennifer Walker-Journey
On December 11, 2008, the Food and Drug Administration (FDA) issued a safety alert calling for a black box warning on prescription oral sodium phosphate (OSP) products used to prepare the bowel prior to colonoscopies following reports of a serious form of kidney injury in patients who had taken OSP products.
The black box warning fell on Salix Pharmaceuticals’ prescription OSP brands Visicol and Osmo Prep, and serious warning was placed on over-the-counter OSP products such as Fleet Phospho-soda and Fleet Accu-Prep. The serious adverse event that was occurring in patients repeatedly over the years was a serious form of kidney injury now known as acute phosphate nephropathy.
Phosphate nephropathy occurs when the kidneys have been severely damaged by the formation of phosphate crystals within the renal tubes. The deposits may result in reduced kidney function. The pieces of calcium may also lead to the formation of stones, or nephrolithiasis. The calcium pieces can damage the nephron and can cause acute renal failure. When the kidney damaged by phosphate nephropathy is biopsied, the pathological findings are typical of nephrocalcinosis.
Imaging tests such as films and CT scans of the abdomen can help identify the disorder. Other tests can help determine the severity. Prognosis varies depending on the extent of complications and the cause of the disorder. Possible complications include acute renal failure, chronic renal failure, kidney stones and obstructive uropathy. Affected individuals may experience suddenly decreased urine output and decreased consciousness.