An FDA is investigating the dialysis division of drugmaker Fresenius after learning that it warned doctors at its own dialysis clinics in November of an increased risk from the way they were using one of its treatments. It didn't provide the same notification to other clinics until March after the FDA received an anonymous copy and intervened, The New York Times reports, citing the initial report of RenalWeb. The German company is the leader in dialysis supplies and equipment and its own clinics treat more than a third of the estimated 400,000 Americans receiving dialysis. Fresenius found that some doctors were not accounting for the higher levels of bicarbonate its GranuFlo product used in dialysis and so some patients were getting too much. Its "urgent" warning to its own doctors said that 941 patients in 2010 had cardiac arrest and tracked the problem to the increased bicarbonate. The company says it had no way of knowing whether doctors outside of its clinics might be over prescribing bicarbonate. Story | More