phosphate binder phosphate binder phosphate binders are medications used to reduce the absorption of dietary phosphate; they are taken along with meals and snacks. they are frequently used in people with chronic kidney failure (ckf), who are less able to excrete phosphate, resulting in an elevated serum phosphate. mechanism of action these agents work by binding to phosphate in the gi tract, thereby making it unavailable to the body for absorption. hence, these drugs are usually taken with meals to bind any phosphate that may be present in the ingested food. phosphate binders may be simple molecular entities (such as magnesium, aluminium, calcium, or lanthanum salts) that react with phosphate and form an insoluble compound. phosphate binders such as sevelamer may also be polymeric structures which bind to phosphate and are then excreted. medical use for people with chronic kidney failure, controlling serum phosphate is important because it is associated with bone pathology and regulated together with serum calcium by the parathyroid hormone (pth). they are also used in hypoparathyroidism which presents with hypocalcemia with hyperphosphatemia. adverse effects with regard to phosphate binders, aluminium-containing compounds (such as aluminium hydroxide) are the least preferred because prolonged aluminium intake can cause encephalopathy and osteomalacia. if calcium is already being used as a supplement, additional calcium used as a phosphate binder may cause hypercalcemia and tissue-damaging calcinosis. one may avoid these adverse effects by using phosphate binders that do not contain calcium or aluminium as active ingredients, such as lanthanum carbonate or sevelamer. choice of agent there have been limited trials comparing phosphate binders to placebo in the treatment of hyperphosphatemia in people with chronic kidney disease. when compared with people receiving calcium-based binders, people taking sevelamer have a reduced all-cause mortality. types summary of common oral phosphate binders phosphate binderbrandsadvantagesdisadvantages aluminum saltsalucapscalcium freerisk of aluminum toxicity basaljelhigh binder efficiency regardless of phrequires frequent monitoring-extra cost cheap moderate tablet burden calcium carbonatecalcichewaluminum freecalcium containing-potential risk of hypercalcemia and ectopic calcification titralacmoderate binding efficacyparathyroid hormone oversuppression relatively low costgastrointestinal side effects moderate tablet burdenefficacy ph dependent chewable calcium acetatelenal acealuminum freecalcium containing-potential risk of hypercalcemia and ectopic calcification phoslohigher efficacy than calcichew/sevelamerparathyroid hormone oversuppression moderately cheapgastrointestinal side effects lower calcium load than calcium carbonatelarge tablets & capsules, nonchewable formulation sevelamer hydrochloride/sevelamer carbonaterenagelaluminium and calcium freerelatively costly renvelano gastrointestinal absorptionhigh pill burden moderate efficacylarge tablets, nonchewable formulation reduces total and low-density lipoprotein cholesterolgastrointestinal side effects binds fat-soluble vitamins lanthanum carbonatefosrenolaluminum and calcium freerelatively costly minimal gastrointestinal absorptiongastrointestinal side effects high efficacy across full ph rangelarger tablet size may cause choking if not chewed well chewable formulation palatable low tablet burden ferric citrate auryxia iron based very costly tablets can be toxic to young children stool discoloration - may turn them black, obscuring intestinal bleeding calcium acetate/magnesium carbonate