Treatment of Severe Iron Deficiency Anemia

Immediate Management

The American Gastroenterological Association recommends initiating ferrous sulfate 200 mg once daily as first-line therapy for severe iron deficiency, which is the most cost-effective and evidence-based approach 1
The American Gastroenterological Association suggests adding vitamin C (ascorbic acid) 500 mg with each iron dose to enhance absorption, particularly in cases with severely depleted iron stores 2, 1
The guideline recommends taking iron on an empty stomach for optimal absorption, though taking with food is acceptable if gastrointestinal side effects occur 1
Alternative formulations (ferrous gluconate or ferrous fumarate) are equally effective if ferrous sulfate is not tolerated 2, 1

Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment, according to the American Gastroenterological Association 2, 1
If no response occurs within 4 weeks, the American Gastroenterological Association recommends assessing for non-adherence, continued blood loss, or malabsorption 2, 1
The American Gastroenterological Association suggests monitoring hemoglobin and red cell indices every 3 months for the first year after correction, then again after another year 2, 1

The American Gastroenterological Association recommends performing bidirectional endoscopy (gastroscopy and colonoscopy) as first-line investigation to exclude gastrointestinal malignancy, which is the most common cause of iron deficiency in postmenopausal women 4, 5, 3
The American Gastroenterological Association suggests screening for celiac disease with tissue transglutaminase antibody (IgA type) and total IgA level, as celiac disease is found in 3-5% of iron deficiency cases 3, 1

The American Gastroenterological Association recommends continuing oral iron for 3 months after hemoglobin and MCV normalize to fully replenish iron stores 2, 1
The American Gastroenterological Association advises against stopping therapy when hemoglobin reaches normal range, as this is a common pitfall that leads to recurrent deficiency 1

The American Gastroenterological Association recommends against prescribing multiple daily doses of oral iron—once-daily dosing improves tolerability with equivalent efficacy 1
The American Gastroenterological Association advises against continuing oral iron indefinitely without response—reassess after 4 weeks and switch to IV iron if hemoglobin fails to rise by 2 g/dL 1
The American Gastroenterological Association suggests not overlooking vitamin C supplementation when oral iron response is suboptimal, as this significantly enhances absorption 2, 1
The American Gastroenterological Association recommends not failing to investigate the underlying cause while supplementing iron—gastrointestinal malignancy must be excluded in postmenopausal women 4, 5, 3