US FDA warns of kidney damage in bowel cleansers

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US FDA warns of kidney damage in bowel cleansers

Thu Dec 11, 2008 3:03pm EST


WASHINGTON, Dec 11 (Reuters) - Some sodium-based bowel cleansing products used before colonoscopies can cause kidney damage and must carry a stern warning on the packaging, the U.S. Food and Drug Administration said on Thursday.

It said it would require the warnings on Salix Pharmaceuticals Ltd's (SLXP.O: Quote, Profile, Research, Stock Buzz) Visicol and OsmoPrep prescription products to caution about the risk of acute phosphate nephropathy, a type of kidney injury.

"The agency is equally concerned about the risks associated with the use of (OSP) oral sodium phosphate products that are available over-the-counter, for example, (C.B. Fleet and Co.'s) Fleet Phospho-soda, when used at higher doses for bowel cleansing," the FDA said in a statement.

So-called "black box" warnings on medicine packaging are meant to bring serious dangers of a product to the attention of doctors and patients. Drinking plenty of fluids can help prevent the injuries, the FDA said.

The FDA said it had received 20 reports of kidney damage in people who had used the products since 2006. Commonly used drugs such as arthritis pills and diuretics raise the risk, the FDA's Dr. Joyce Korvick told reporters.

People over the age of 55 and people who already have kidney function problems are at special risk, she added.

"The available data do not show a risk of acute kidney injury when these over-the-counter products are used at the lower doses for laxative use," it added.

But when used to cleanse bowels before a colonoscopy, they carry higher risks, the agency said.

"In light of the continued receipt of reports of acute phosphate nephropathy, FDA is recommending that consumers not use over-the-counter OSPs for bowel cleansing," it said.

Dr. Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research, said the injuries were rare.

"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," Woodcock said in a statement.

"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."

Regular colonoscopies are recommended for all people over the age of 50 and for people at higher than average risk of colon cancer. The procedure, done under sedation, involves threading a little camera through the rectum and up into the colon to find precancerous growths, which can then be removed.

The OSP laxatives can cause dehydration and high levels of phosphate in the kidneys -- which can produce damaging crystals in the organ.

The FDA said it was requiring that Salix do a post-marketing trial to check the risk of acute kidney injury. (Reporting by Maggie Fox, editing by Will Dunham and David Storey)

http://www.reuters.com/article/rbssHealthcareNews/idUSN1140448820081211