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Monday, December 29, 2008

Laxative Colonoscopy Prep Products and Kidney Damage

Laxatives are one of the most commonly overused products sold to consumers, over-the-counter (OTC). These same products, and others available by prescription only, have caused serious side effects associated with kidney damage (nephropathy) and dehydration.

The products are particularly risky for the elderly and people with existing heart, kidney and some gastrointestinal problems.

Since colon cancer prevention and screening are important health concerns, consumers are encouraged to be educated about using these products.

Osmolar Phosphate Laxatives: Keeping Water in its Place

Osmolarity is a fancy word that refers to a basic rule of physics and biology and it is about how fluids - in this case it’s water – move in and out of cells based on the presence of electrolytes, most often sodium and potassium. Phosphorus and calcium are two other electrolytes that are important health and often work together.

Your body depends on a delicate balance of trace elements and enzyme reactions to keep humming like a top. When this balance is altered you run the risk of dehydration and problems with the way your kidneys work.

Simply put, when you ingest a large amount of sodium containing foods or liquids, the kidneys work to flush the excess sodium out of the body. It does this by removing fluid from inside the cells, from your tissues and organs and moves it through the kidneys or the gastrointestinal tract. This may lead to excessive urination and diarrhea. In the process you lose not only the water but your electrolyte balance is altered.

Phosphorus and calcium reactions with dehydration may lead to the formation of crystals or “stones” and reduction of kidney function.

Laxatives often become the culprit in these cases, especially for the elderly, those with heart failure, people with kidney problems, and people using prescription or over-the-counter (OTC) medication affecting kidney function (diuretics for example).

Oral Sulfur Phosphates as Preps for Screening for Colorectal Cancer

Currently colorectal cancer is the third most common cancer and it is the second leading cause of cancer related deaths, therefore screening and early detection have become an important public health issue.

Thorough bowel cleansing is an important part of preparation for this screening and it is crucial to find a product that is safe and easy use. The difficulty in getting more people to seek the screening may be increased because of concerns with the products.

One very popular laxative has been Fleet’s Phospho-Soda. The C.B. Fleet Co. of Lynchburg, VA recently, in a voluntary action, withdrew its oral, over-the-counter Fleet Phospho-Soda bowel cleansing solutions after FDA regulators warned of potential harm to the kidneys when the Phospho-Soda is used as a bowel cleanser.

While the FDA has not required a recall, Fleet also removed the EZ-Prep Bowel Cleansing System used to clear the bowels before a colonoscopy.

Information found urges anyone using Phospho-soda to review current FDA product information pages. They also state that it is important to follow your doctor’s guidelines and drink at least nine 8-ounce glasses of water daily to prevent dehydration.

The FDA is now moving to have these laxative products relabeled to include warnings and make them available only by prescription.

Other prescription products, Visicol and OsmoPrep, will add the new FDA required warning regarding potential kidney damage to their oral sodium phosphate products.

The concern at the FDA is that oral sodium phosphate products have been connected with kidney function problems such as acute phosphate nephropathy that can cause permanent damage and lifelong dialysis or death. In acute phosphate nephropathy, calcium-phosphate crystals deposit in the renal tubules inside each kidney.

When used as directed or at lower levels, the FDA stated there is no evidence that the OTC laxatives lead to kidney problems. The agency, however, started issuing alerts in 2006. Other data show that product lawsuits for oral sodium phosphate laxatives, including lawsuits where OSP product users developed acute phosphate nephropathy began appearing in 2003.

While Phospho-soda has been the bowel prep product used and recommended by physicians for decades, Fleet is not asking doctors to not recommend the Phospho-soda products.

Gastroenterologists and proctologists have recommended Fleet’s Phospho-soda products for years, especially in patient preparation for screening colonoscopy (a colon cancer screening examination). In a clinical trial the product achieved the highest patient acceptance scores, and cleansing was generally rated as excellent.
However, Fleet Phospho-soda should not be used in patients with congenital megacolon, bowel obstructions, ascites, congestive heart failure or kidney disease.
When problems do not exist, physicians believe the product is good because it is effective, easily tolerated by patients and affordable.

Generally most patients do not like bowel prep products. Some doctors, like Mark Wax MD, suggest the need for “virtual bowel prep”. He adds that “until that becomes an option, patients will have to undergo conventional preparation and that requires making informed decisions about available options.” Wax is associated with a company that offers virtual colonoscopy.

The company states that virtual colon screening is a minimally invasive, safe and more comfortable procedure. Recent studies have shown it to be comparable to conventional colonoscopy for finding polyps larger than one centimeter. The risk of cancer in smaller polyps is almost negligible. With virtual colonoscopy, 100% of the colon surface can be seen. It is estimated that physicians only see 70%-80% of the colon surface with conventional colonoscopy.

Should you have medical questions about using these products, contact your health care provider.

This article is part of a consumer health education series written by Gayle Eversole, DHom, PhD, MH, NP, ND, of Creating Health Institute, in collaboration with Bernstein Liebhard, LLP, who sponsors the consumer advocate website,

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