Treatment of Iron Deficiency Anemia

Start with oral ferrous sulfate 200 mg once daily, which is the preferred first-line treatment due to its effectiveness and low cost. 1

Oral Iron Therapy (First-Line)

Ferrous sulfate 200 mg once daily is the recommended formulation rather than multiple daily doses, as once-daily dosing improves tolerability while maintaining similar effectiveness 1
Take on an empty stomach for optimal absorption, though taking with food is acceptable if gastrointestinal side effects occur 1
Add vitamin C (ascorbic acid) 500 mg with each iron dose to enhance absorption, particularly when response is suboptimal 2, 1
Alternative formulations (ferrous gluconate or ferrous fumarate) are equally effective if ferrous sulfate is not tolerated 2, 1
Continue oral iron for 3 months after anemia correction to fully replenish iron stores 2, 1

Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment 1
If no response occurs within 4 weeks, assess for non-adherence, malabsorption, or ongoing blood loss 1

Switch to IV iron if the patient meets any of these criteria:

Intolerance to at least two different oral iron preparations 1
Inadequate response to oral iron after 4 weeks 1
Inflammatory bowel disease with active inflammation, especially if hemoglobin <10 g/dL 2, 1
Post-bariatric surgery patients with disrupted duodenal iron absorption 1
Celiac disease with inadequate response despite gluten-free diet adherence 1
Ongoing gastrointestinal blood loss exceeding oral replacement capacity 1
Chronic heart failure with iron deficiency (ferritin <100 μg/L or transferrin saturation <20%) - IV iron has demonstrated prognostic benefit 2
Chronic kidney disease, particularly if on dialysis or if GFR <30 mL/min/1.73m² 2
Pregnancy during second and third trimesters if oral iron is inadequate 1, 3

Prefer IV iron formulations that can replace iron deficits with 1-2 infusions 1
Ferric carboxymaltose allows large doses with short infusion times and has a good safety profile 4
Iron dextran can be given as total dose infusion but carries higher risk of anaphylaxis 1
Observe patients for at least 30 minutes after IV iron administration for hypersensitivity reactions 5

Monitor hemoglobin and red cell indices every 3 months for the first year, then again after another year 2, 1
Provide additional iron supplementation if hemoglobin or MCV falls below normal 2, 1
If anemia does not resolve within 6 months despite appropriate therapy, reassess for ongoing blood loss, evaluate for malabsorption syndromes, and consider further gastrointestinal investigation 1

Assessment differs: absolute iron deficiency defined as transferrin saturation ≤20% with ferritin ≤100 μg/L (predialysis/peritoneal dialysis) or ≤200 μg/L (hemodialysis) 2
IV iron is required if oral iron is not tolerated, ineffective, or if dialysis has commenced 2
Management should be coordinated with nephrology team 2

Screen with ferritin and transferrin saturation 2
IV iron is indicated even for functional iron deficiency (not just absolute deficiency) as it improves functional capacity, quality of life, and prognosis 2
Oral iron should be avoided as it is poorly absorbed due to gut edema and frequently causes side effects 2

Treat active inflammation first to enhance iron absorption and reduce iron depletion 1
IV iron is first-line treatment with active IBD and hemoglobin <10 g/dL 1
One-third of patients with active IBD have iron deficiency 2

Start oral low-dose iron (30 mg/day) at first prenatal visit 1
For anemia treatment, use 60-120 mg/day orally 1
IV iron is indicated during second and third trimesters if oral iron is inadequate 1, 3

Do not prescribe multiple daily doses - this increases side effects without improving efficacy 1
Do not stop iron therapy when hemoglobin normalizes - continue for 3 months to replenish stores 2, 1
Do not continue oral iron indefinitely without response - reassess after 4 weeks and switch to IV iron if hemoglobin fails to rise 1
Do not overlook vitamin C supplementation when oral iron response is suboptimal 2, 1
Do not fail to identify and treat the underlying cause while supplementing iron 2, 1
Do not use parenteral iron as first-line unless specific contraindications to oral therapy exist 1

Men and postmenopausal women require gastrointestinal evaluation with upper endoscopy and colonoscopy to exclude malignancy 1, 6
Premenopausal women should be assessed for menstrual blood loss, though menstruation alone may explain iron deficiency 2
Consider celiac disease screening with antiendomysial antibody and IgA measurement 1
Evaluate for use of NSAIDs, anticoagulants, or antiplatelet agents 2