Iron Deficiency Treatment Guidelines

Oral Iron Supplementation

The American Gastroenterological Association recommends ferrous sulfate 200 mg twice daily (contains approximately 65 mg elemental iron per tablet) as the most commonly recommended and cost-effective oral iron supplement 1, 2
Lower doses of ferrous sulfate may be as effective and better tolerated in patients experiencing side effects, with a strength of evidence based on clinical trials 1
Treatment with oral iron should continue for 3 months after iron deficiency has been corrected to ensure replenishment of iron stores, as suggested by the European Society for Clinical Nutrition and Metabolism 1
Ferrous gluconate, ferrous fumarate, polysaccharide-iron complex, and ferrous bisglycinate are alternative oral iron formulations, although ferrous bisglycinate may be better tolerated by some patients but has no evidence of superior efficacy, according to the National Institute of Diabetes and Digestive and Kidney Diseases 2
Once-daily dosing of oral iron is sufficient, and more frequent dosing increases side effects without improving absorption, as recommended by the American College of Gastroenterology 2
Taking iron with 80 mg vitamin C (ascorbic acid) on an empty stomach may improve absorption, with a moderate strength of evidence based on human studies 2, 3
Avoid consuming tea or coffee within one hour after taking iron supplements as they inhibit absorption, as advised by the European Food Safety Authority 2

The American Society of Hematology recommends intravenous iron for patients who are intolerant to oral iron preparations, have failed to respond to oral iron, or have conditions with impaired absorption, with a high strength of evidence based on clinical trials 2, 3
Indications for IV iron also include active inflammatory bowel disease, when iron loss exceeds oral iron absorption capacity, and critically ill patients with iron deficiency confirmed by low hepcidin levels, as suggested by the Society of Critical Care Medicine 2, 4
Ferric carboxymaltose, iron sucrose, ferric derisomaltose, ferumoxytol, and iron dextran are IV iron formulations with different dosing regimens, as recommended by the American Journal of Hematology 2, 5

For enteral nutrition, the European Society for Clinical Nutrition and Metabolism recommends providing 18-30 mg iron per day with 1500 kcal, with a moderate strength of evidence based on human studies 4
For parenteral nutrition, the American Society for Parenteral and Enteral Nutrition recommends providing at least 1 mg/day of elemental iron, with a high strength of evidence based on clinical trials 4
For female athletes, the International Society of Sports Nutrition recommends considering 100 mg/day iron in divided doses for 8-12 weeks with vitamin C supplementation, with a moderate strength of evidence based on human studies 6, 7
For pregnant women, the Centers for Disease Control and Prevention recommend low-dose supplementation (30 mg/day) which may be as effective as higher doses while reducing side effects, with a high strength of evidence based on clinical trials 8
Hemoglobin should increase by 1 g/dL within 2 weeks of supplementation in anemic patients, and ferritin should increase within one month in adherent patients on oral iron, as recommended by the American College of Gastroenterology 2
After normalization, monitor hemoglobin and red cell indices at 3-month intervals for 1 year, then after another year, as suggested by the European Society for Clinical Nutrition and Metabolism 1