Ferric citrate is used to control high blood levels of phosphorus in people with chronic kidney disease who are on dialysis (medical treatment to clean the blood when the kidneys are not working properly). Ferric citrate is also used to treat iron-deficiency anemia (a lower than normal number of red blood cells due to too little iron) in adults with chronic kidney disease (damage to the kidneys which may worsen over time and may cause the kidneys to stop working) who are not on dialysis. Ferric citrate is in a class of medications called phosphate binders and iron replacement products. It works to control high blood levels of phosphorus by binding phosphorus that you get from foods in your diet and prevents it from being absorbed into your blood stream. It works to treat iron-deficiency anemia by replenishing iron stores so that the body can make more red blood cells.