How is iron malabsorption treated?

Treatment of Iron Malabsorption

Intravenous iron is the primary treatment for iron malabsorption, as oral iron supplementation will be ineffective when absorption is impaired. 1

When to Use Intravenous Iron for Malabsorption

IV iron should be initiated in the following malabsorption scenarios:

• Post-bariatric surgery patients, particularly those with procedures bypassing the duodenum and proximal jejunum where iron absorption occurs 1, 2
• Active inflammatory bowel disease, where inflammation impairs intestinal iron absorption 1, 2
• Celiac disease with inadequate response to gluten-free diet, though adherence to gluten-free diet should be ensured first to improve absorption 1
• H. pylori infection that interferes with iron absorption (treat the infection concurrently) 2
• Failure of oral iron therapy, defined as lack of hemoglobin increase by 1 g/dL within 2 weeks or failure of ferritin to increase within one month in adherent patients 1

IV Iron Administration

Formulations that can replace iron deficits with 1-2 infusions are preferred due to similar efficacy and safety profiles across products 1

• Dosing varies by formulation but typically ranges from 200-1000 mg total dose depending on the specific product and clinical scenario 3
• Mild infusion reactions (occurring in approximately 1:200 patients) can be managed by stopping the infusion and restarting 15 minutes later at a slower rate 1
• Major reactions are rare (approximately 1:200,000) and represent complement activation-related pseudo-allergy rather than true allergy 1
• Avoid diphenhydramine as its side effects can be mistaken for worsening reactions; use corticosteroids for severe reactions instead 1

Optimizing Oral Iron When Absorption is Partially Preserved

If malabsorption is partial rather than complete, optimize oral iron administration:

• Take iron on an empty stomach for best absorption, though some patients tolerate it better with meals 1
• Add 500 mg vitamin C to allow iron absorption even when calcium or fiber is present 1
• Taking iron with meat protein improves absorption 1
• Avoid tea and coffee within one hour of iron administration as they powerfully inhibit absorption 1
• Dose once daily only, as hepcidin levels remain elevated for 48 hours after oral iron, blocking further absorption and increasing side effects without benefit 1
• Use ferrous iron salts (ferrous sulfate, ferrous fumarate, or ferrous gluconate) as first-line agents 1

Disease-Specific Considerations

• Celiac disease: Ensure strict gluten-free diet adherence first, then attempt oral iron based on severity and tolerance before advancing to IV iron 1
• Inflammatory bowel disease: IV iron is indicated when active inflammation is present 1, 2
• Post-bariatric surgery: IV iron should be used initially rather than attempting oral supplementation 1, 2

Monitoring Response

• Hemoglobin should increase by 1 g/dL within 2 weeks of appropriate iron supplementation 1
• Ferritin should increase within one month in adherent patients on oral iron 1
• If these parameters are not met, switch to IV iron 1

Important Caveats

The oral iron absorption test can determine the degree of iron absorption and guide the decision between oral versus IV therapy, though it is not clearly standardized 4. Treating the underlying cause of malabsorption is essential - iron supplementation alone without addressing the root cause (such as untreated celiac disease or active H. pylori infection) will result in continued therapeutic failure 1, 2, 5.