FDA Warns Against Bowel Cleansing Drugs for Colonoscopy
Bowel cleansing products that contain sodium phosphate have received a stern warning from the FDA about the potential of the products to cause acute kidney damage. Two products available by prescription, Visicol and OsmoPrep have received "black box" warnings from the FDA. The over-the-counter bowel cleanser, Fleet Phospho-soda, is also not recommended for consumer use because of the same potential for kidney injury as seen in the prescription bowel cleansers.
The FDA reveals they have received 20 reports of sudden kidney injury within the past two years, associated with the use of OsmoPrep and Visicol. Both products were approved by the FDA in 2006. Since that time, nineteen cases of kidney failure have been confirmed by biopsy, occurring within hours or weeks after the prescriptions were used for bowel cleansing.
FDA officials claim that not everyone is at risk. Charles Ganley, MD, director of the FDA's Office of Nonprescription Products says, "The majority (of patients) don't run into problems." Those at risk include anyone over age 55, people with colon problems causing a delay in bowel evacuation, anyone with acute colitis, and those who are dehydrated.
Precautions are especially important for patients who take medication that already can affect the kidneys, including diuretics, ACE inhibitors (blood pressure medicine), and anti-inflammatory drugs (NSAIDS), such as Ibuprofen and Naproxen.
Polyethylene glycol preparations that can be safely used for bowel cleansing include Golytely, Colyte, Nulytely, Trilyte, and Halflytely, none of which contains sodium phosphate.
In January, 2014, the FDA also issued an alert for over the counter products containing sodium phosphate or sodium biphosphate, warning again of the risks of dehydration that can occur from taking more than the recommended dose. The products are sold for constipation and can be taken orally or used in enema preparations. An example is "Fleet" enema.
The FDA says anyone over age 18, not at risk for kidney damage, can still use the colon cleanser in preparation for colonoscopy.
Salix Pharmaceuticals manufactures Visicol and OsmoPrep. The FDA has asked the company to study the products to find out how they cause kidney damage, and what needs to be done to protect against the kidney condition, known as phosphate nephropathy. No other over the counter laxative is included in the FDA warning.
According to Janet Woodcock, M.D., director, FDA's Center for Drug Evaluation and Research "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. 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."
The kidneys are important for removing toxins from the body and for regulating blood pressure. If you have existing hypertension, diabetes or are on medications that require regular blood testing to check kidney function you may be at risk.
If you have experienced kidney injury associated with the colon cleansers mentioned the FDA encourages you to report it to their MedWatch Adverse Event Reporting program online, by regular mail, fax or phone.
Updated January 24, 2014