FDA to add 'black-box' warnings to bowel-cleansing drugs
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WASHINGTON - Federal health officials said yesterday that they will add the sternest safety warnings available to prescription 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 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
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."
C.B. Fleet said it was voluntarily withdrawing its Fleet Phospho-soda and Fleet Phospho-soda EZ-Prep Bowel Cleaning System.
FDA officials said some patients are not following directions outlined on the drugs, which instruct patients to drink up to half a gallon of water with the tablets.
"The question is one of getting people to drink enough fluids," said Dr. Joyce Korvick, director of FDA's digestive products. "Some patients that take these pills feel perhaps you don't need to drink as much as you really do to avoid these side effects."
Korvick said kidney damage can occur within days or weeks of using the drugs, but symptoms - such as lethargy, drowsiness, and swelling - may not appear until much later.
The FDA is requiring Salix to distribute a medication guide warning patients about the risks of the drugs. The company also must conduct a follow-up study looking at which patients are most vulnerable to kidney damage.
Combined sales of OsmoPrep and Visicol totaled more than $27 million in 2007, according to the company's earnings report.
