Ferric carboxymaltose injection is used to treat iron-deficiency anemia (a lower than normal number of red blood cells due to too little iron) in adults and children 1 year of age and older who cannot tolerate or who could not successfully be treated with iron supplements taken by mouth. This medication is also used to treat iron deficiency anemia 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.