OsmoPrep was licensed in 2006 by the US Food and Drug Administration. Basically the drug allows doctors to get a better view of the colon by inducing loose bowels. Two years after OsmoPrep was approved, the FDA publicly announced the addition of a black box warning of kidney damage to the labeling of these products.
OsmoPrep contains phosphate, known to damage kidneys
OsmoPrep tablets contain a combination of sodium biphosphate and sodium phosphate, both are forms of phosphorus, which is a naturally occurring substance that is important in every cell in the body. On the other hand, sodium phosphate is also an ingredient that had previously been linked to several cases of acute renal failure.
OsmoPrep tablets are used for cleansing of the colon in preparation for a colonoscopy. A colonoscopy is an examination of the inside of the colon to check for colon cancer and other abnormalities. It is necessary to clean out the colon in order for the doctor to have a clear view of the walls of the colon. The tablets are taken with any clear liquid and works by causing diarrhea so that all the stool can be emptied from the colon. They are in a class of medications called saline laxatives.
The risk was known at atleast 1 year before FDA approved OsmoPrep
The FDA approved this drug a year after the active ingredient was linked to acute renal failure characterized by excess phosphate. Sodium phosphate causes serious kidney damage in some people. In some cases, this kidney damage was permanent resulting in dialysis treatment (treatment to remove waste from the blood when the kidneys are not working well). Some people developed kidney damage within a few days after their treatment, and others developed kidney damage up to several months after exposure to OsmoPrep. A study in the November 2005 issue of the Journal of the American Society of Nephrology established the link between phosphate containing laxatives and kidney failure.
In an interview with Renal Wire immediately following the study’s publication, principal investigator Dr. Glen Markowitz said that in light of these findings, physicians should exercise extreme caution when prescribing oral bowel purgatives containing sodium phosphate in those over 64 years of age.
Furthermore, at 16-month follow-up, none of the patients had regained normal renal function and four had gone on to require permanent hemodialysis.
Even though one of the cases of kidney failure reported in the study was in a patient taking Visicol tablets, Dr. Doug Bettenhausen, Salix Pharmaceuticals executive director, medical affairs, said this case must be put into context. “This is one case out of over 1.8 million uses, so it is extremely rare,” he told Renal Wire . He went on to say that it is not clear from the study whether the preparation protocols for either the OSPS or Visicol, which call for 8 ounces of fluid to be taken with three tablets every 15 minutes for a total of 40 tablets over a two-day period (20 each day), were followed.
According to Bettenhausen, following preparation protocols to ensure adequate hydration is critical to protecting kidney function and dramatically “decreases if not eliminates” the chances of renal complications.
OsmoPrep had a more favorable side-effect profile than Visicol, with lower rates of nausea, vomiting, and abdominal bloating and pain. It also contains approximately 20% less sodium phosphate, which will further reduce any potential renal risk, he added.
However, regardless of the findings of this particular doctor, whom works for the pharmaceutical company that manufactures this drug; one should not forgot that the active ingredient, was in fact linked to kidney failure, and therefore one should take extreme caution when considering taking this medication