Iron Deficiency Anemia Treatment

Introduction

Iron deficiency anemia is a common condition, affecting 5-10% of menstruating women, and its causes should be investigated according to standard guidelines 1

Formulations and Absorption

Ferrous gluconate and ferrous fumarate are equally effective as ferrous sulfate in treating iron deficiency anemia, with liquid preparations being better tolerated when tablets are not 1
Adding vitamin C (ascorbic acid) to iron supplements can enhance iron absorption 1
Plant-based diets require approximately 1.8 times more dietary iron due to lower bioavailability, and patients should be advised to increase their iron intake accordingly, as reported by the Institute of Medicine and other guidelines 2, 1

Expected Response and Monitoring

Hemoglobin levels should rise by 2 g/dl after 3-4 weeks of iron therapy, indicating a positive response to treatment 1
Target values include hemoglobin >12 g/dL for women and >13 g/dL for men, ferritin >100 μg/L, and transferrin saturation >20%, with a moderate strength of evidence, according to the American Journal of Kidney Diseases and Clinical Gastroenterology and Hepatology 3, 4

Diagnostic Considerations

Those under 45 years without GI symptoms should undergo antiendomysial antibody testing to exclude celiac disease, a potential cause of iron deficiency anemia 1
Bidirectional endoscopy (colonoscopy and upper endoscopy) is the mandatory first step to investigate the underlying cause in asymptomatic males with iron deficiency anemia, as recommended by the American Gastroenterological Association 5
Initial evaluation should include serologic testing for celiac disease if bidirectional endoscopy is negative, as recommended by the American Gastroenterological Association 5
Potential causes of iron deficiency anemia include peptic ulcer disease, gastric/esophageal cancer, esophagitis, gastritis, angiodysplasia, colonic cancer/polyps, inflammatory bowel disease, NSAID use, celiac disease, and gastric atrophy, as listed by the European Society of Gastrointestinal Endoscopy 1

Treatment

Iron supplementation is recommended for individuals with iron deficiency anemia, with the goal of replenishing iron stores and improving hemoglobin levels, as supported by the Centers for Disease Control and Prevention, the American College of Sports Medicine, and the Clinical Nutrition guideline society 6, 7, 8
The recommended daily dose of elemental iron is 60-120 mg for adults, with a 325 mg tablet providing 65 mg of elemental iron, and iron therapy should be continued for 2-3 months after hemoglobin normalizes to replenish iron stores, as recommended by the Centers for Disease Control and Prevention 8
Alternative dosing regimens include 200 mg of elemental iron daily in 2-3 divided doses for adults, or as a single daily dose of ferrous sulfate 200 mg (providing 65 mg elemental iron) with vitamin C to enhance absorption, as recommended by the American Journal of Kidney Diseases and the American College of Physicians 3, 4
Pediatric dosing is 2-3 mg/kg/day of elemental iron for patients with iron deficiency anemia, as recommended by the American Academy of Pediatrics 3
Athletes and active women may require higher daily iron intake (22 mg/day), as suggested by the American College of Sports Medicine 6
Pregnant women should start with 30 mg/day of iron supplements at the first prenatal visit and increase to 60-120 mg/day for anemia during pregnancy, then decrease to 30 mg/day once hemoglobin normalizes for the gestational stage, as recommended by the Centers for Disease Control and Prevention 8

Special Considerations

For patients with chronic kidney disease, oral iron may be less effective, and IV iron should be considered if serum ferritin is >100 ng/mL, with a moderate strength of evidence, according to the American Journal of Kidney Diseases 3
For patients with inflammatory bowel disease or after bariatric surgery, IV iron is preferred, with a high strength of evidence, according to Clinical Gastroenterology and Hepatology 4

IV iron is indicated as first-line therapy for patients with active infection, hemoglobin below 10 g/dL, need for rapid correction of anemia, and previous intolerance to oral iron, with dosing based on weight and hemoglobin level, as shown in the table:

Hemoglobin g/dL	Body weight <70 kg	Body weight ≥70 kg
10-12 [women]	1000 mg	1500 mg
10-13 [men]	1500 mg	1500 mg
7-10	1500 mg	2000 mg	[5, 9]

Ferric carboxymaltose (Ferinject) may be administered up to 1000 mg in a single 15-minute infusion, and is preferred due to its ability to administer high doses, lower risk of adverse reactions, and faster improvement in hemoglobin levels 10, 9
Iron sucrose (Venofer) may be administered 200 mg over 10 minutes 10
Iron dextran (Cosmofer) may be administered 20 mg/kg over 6 hours (can also be given intramuscularly) 10

Lifestyle Modifications

Increase intake of iron-rich foods, including heme iron (red meat, poultry, fish) and non-heme iron (leafy greens, legumes, fortified cereals), and consume vitamin C-rich foods with meals to enhance absorption, as recommended by the International Society of Sports Nutrition and The Lancet Planetary Health 6, 11

Common Pitfalls

Stopping treatment too early before iron stores are replenished, with a high strength of evidence, according to Clinical Gastroenterology and Hepatology 4
Using divided doses when a single daily dose may be better tolerated, with a moderate strength of evidence, according to Clinical Gastroenterology and Hepatology 4
Failing to add vitamin C to enhance absorption, with a high strength of evidence, according to Gut and Clinical Gastroenterology and Hepatology 4, 10
Using parenteral iron when oral therapy would be effective, with a moderate strength of evidence, according to the American Journal of Kidney Diseases and Clinical Gastroenterology and Hepatology 3, 4
Inadequate dosing that underestimates total iron deficit, with a moderate strength of evidence, according to the American Journal of Kidney Diseases and Clinical Gastroenterology and Hepatology 3, 4
Delaying iron treatment until the underlying condition resolves can prolong anemia symptoms and recovery 9

Praxis Medical Insights