FDA Puts Black Box Warning on Bowel-Clearing Drugs

WASHINGTON -- Federal health officials said they will add the sternest safety warnings available to drugs used before colonoscopies, following reports of kidney damage in several patients.

The Food and Drug Administration said it has received more than 20 reports of a serious form of kidney failure among patients taking the bowel-cleansing drugs, known as oral phosphate products.

The new boxed warning label will apply to Visicol and OsmoPrep -- both prescription tablets made by Salix Pharmaceuticals. The label warns that the drugs should be used with caution in patients older than 55, those who suffer from dehydration and kidney disease, and those who take medications that affect the kidneys.

Regulators said they are also concerned about the risks of over-the-counter bowel cleansers, such as Fleet Phospho-soda, made by C.B. Fleet Company Inc.

"There are many people who use these and use them fine," said Charles Ganley, who heads FDA's office of nonprescription products. "But there are people who are developing severe kidney injury, and it's important we try and identify who is at risk."