The ins and outs of ferric citrate.

Ferric citrate is used clinically for the treatment of hyperphosphatemia in patients with chronic kidney disease and is approved as an oral iron replacement product for patients with iron-deficiency anemia. In this issue of Kidney International, Hanudel and colleagues take advantage of genetic models with and without chronic kidney injury to demonstrate that the enteric absorption of iron delivered by ferric citrate is dependent on ferroportin expression and does not involve paracellular iron transport.