Iron requirements in erythropoietin therapy.

When erythropoietin (epoetins or darbepoetin) is used to treat the anemias of chronic renal failure, cancer chemotherapy, inflammatory bowel diseases, HIV infection and rheumatoid arthritis, functional iron deficiency rapidly ensues unless individuals are iron-overloaded from prior transfusions. Therefore, iron therapy is essential when using erythropoietin to maximize erythropoiesis by avoiding absolute and functional iron deficiency. Body iron stores (800-1200 mg) are best maintained by providing this much iron intravenously in a year, or more if blood loss is significant (in hemodialysis patients this can be 1-3 g). There is no ideal method for monitoring iron therapy, but serum ferritin and transferrin iron saturation are the most common tests. Iron deficiency is also detected by measuring the percentage of hypochromic red blood cells, content of hemoglobin in reticulocytes, soluble transferrin receptor levels, and free erythrocyte protoporphyrin values, but iron overload is not monitored by these tests. Iron gluconate and iron sucrose are the safest intravenous medications.