Dietary restriction of phosphorus, although important, is difficult to accomplish because dialysis patients are encouraged to consume a relatively [[high protein diet]] in order to prevent protein malnutrition. Similarly, intermittent hemodialysis alone does not adequately control serum phosphorus in most patients. However, the use of more frequent dialysis such as short daily dialysis or long nocturnal hemodialysis may be effective in achieving the recommended goal serum phosphorus level without the use of phosphate binders. Unfortunately, these dialysis modalities are still in the experimental stage, and have not yet been widely applied in clinical practice. Consequently, phosphate binders are routinely prescribed for most patients with end-stage renal disease (ESRD) in order to reduce intestinal absorption of dietary phosphorus and prevent hyperphosphatemia.
The ideal phosphate binder should bind most dietary phosphate in the intestine without producing significant adverse effects. It should also be relatively inexpensive, because most dialysis patients usually consume relatively large daily doses of the binder. Unfortunately, none of the currently used phosphate binders fulfill all these requirements. This is best exemplified by aluminum hydroxide, which is probably the most cost-effective phosphate binder but has largely been abandoned because of the risks of aluminum intoxication with encephalopathy and osteomalacia. As a result, calcium acetate and calcium carbonate replaced aluminum hydroxide as the most widely prescribed phosphate binders.
If use aluminum hydroxide, give 2 doses. Stop sevelamer
However, recent concern over the possible risks of calcium loading from these binders has led to introduction of the considerably more expensive non-calcium, non-aluminum phosphate binder, sevelamer hydrochloride.
In clinical practice, calcium acetate and sevelamer hydrochloride are currently the two most commonly used phosphate binders. Previous studies comparing these two binders suggested that they are equally effective in controlling serum phosphorus. Unfortunately, previous trials did not allow for adequate comparison of these binders because by design they were either open-label, single-arm titration, or placebo-controlled. Moreover, in most of these studies, sevelamer hydrochloride was not usually effective in controlling serum phosphorus to the recommended goal of 5.5 mg/dL or less. Given the enormous financial burden of caring for the ever-increasing dialysis population in the United States, it is imperative that the newer and more expensive therapy be shown to be at least equally efficacious in achieving the desired goals for serum phosphorus before recommending it for widespread use in patients with chronic kidney disease (CKD) on maintenance hemodialysis.