Drug used for high potassium questioned

The study was led by Dr. Richard Sterns of the University of Rochester School of Medicine and Dentistry.

The researchers said high potassium levels (hyperkalemia) are a potentially life-threatening problem, commonly occurring in patients with kidney disease. Ion exchange resins, mixed with a cathartic called sorbitol, have long been used to treat the condition with millions of doses prescribed every year in the United States.

"These agents came into widespread use in 1958 -- four years before drug manufacturers were required to prove the effectiveness of their products before gaining FDA approval," Sterns said. "Their approval was essentially 'grandfathered.' "

Last year, the FDA issued a warning against giving ion exchange resins with sorbitol, based on reported cases of potentially fatal bowel injury. Yet pre-mixed preparations of the resin with sorbitol are still marketed and widely used.

"We found no rigorous scientific evidence that ion exchange resins are effective in ridding the body of excess potassium," Sterns added. "In fact, we found some evidence showing that, on rare occasions, they might be harmful."

The study that included Maria Rojas, Paul Bernstein, and Sreedevi Chennupati is to be reported in an upcoming issue of the Journal of the American Society of Nephrology.

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