What is the recommended treatment for a patient with iron deficiency anemia who is unable to absorb iron, considering intravenous iron supplementation with Venofer (iron sucrose)?

Intravenous Iron Therapy for Malabsorption

Yes, full-dose intravenous Venofer (iron sucrose) is appropriate for a patient who cannot absorb oral iron, but the specific dosing regimen depends on the underlying condition causing malabsorption and whether the patient has chronic kidney disease.

Dosing Regimen Based on Clinical Context

For Non-Dialysis Patients with Malabsorption

• Administer Venofer 200 mg undiluted as a slow intravenous injection over 2 to 5 minutes or as an infusion of 200 mg in a maximum of 100 mL of 0.9% NaCl over 15 minutes, given on 5 different occasions over a 14-day period (total dose: 1000 mg). 1
• Alternatively, 500 mg of Venofer diluted in a maximum of 250 mL of 0.9% NaCl can be infused over 3.5 to 4 hours on Day 1 and Day 14, though there is limited experience with this regimen. 1

Conditions Requiring IV Iron as First-Line Therapy

• Active inflammatory bowel disease with hemoglobin <10 g/dL is an absolute indication for IV iron because inflammation-induced hepcidin elevation severely impairs oral iron absorption. 2, 3
• Post-bariatric surgery patients should receive IV iron due to disrupted duodenal absorption mechanisms. 2
• Celiac disease with ongoing gluten exposure or inadequate response to oral iron despite gluten-free diet adherence requires IV iron. 2
• Chronic kidney disease patients, particularly those on hemodialysis, require IV iron due to functional iron deficiency and inflammation-mediated hepcidin upregulation. 3

Alternative IV Iron Formulations

While Venofer is appropriate, consider IV iron preparations that can replace iron deficits in 1-2 infusions rather than multiple infusions to minimize risk and improve convenience. 2

• Ferric carboxymaltose (Ferinject) allows 1000 mg single doses delivered within 15 minutes, making it more convenient than iron sucrose which requires multiple visits. 4, 2
• Iron dextran (Cosmofer) can replenish iron in a single total dose infusion (up to 20 mg/kg over 6 hours), but carries a higher risk of anaphylaxis (0.6-0.7%). 4
• Iron sucrose requires a maximum single dose of 200 mg over 10 minutes, necessitating multiple infusions to achieve total iron repletion. 4

Safety Considerations

• Resuscitation facilities must be available when administering any IV iron formulation, as anaphylaxis may occur, though true anaphylaxis is rare (0.6-0.7%). 4, 3
• Most reactions are complement activation-related pseudo-allergy (infusion reactions) that respond to slowing the infusion rate rather than true anaphylaxis requiring epinephrine. 2
• All IV iron formulations have similar overall safety profiles. 2, 5
• Monitor phosphate levels, as IV iron formulations (especially ferric carboxymaltose) have been associated with hypophosphatemia. 6

Expected Response and Monitoring

• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of IV iron treatment. 2
• Monitor hemoglobin and red cell indices every 3 months for the first year after correction, then again after another year. 4, 2
• Venofer treatment may be repeated if iron deficiency recurs. 1

Critical Pitfalls to Avoid

• Do not use oral iron in patients with active inflammatory bowel disease and hemoglobin <10 g/dL, as this is ineffective and potentially harmful. 2
• Do not delay IV iron therapy in patients with documented malabsorption—oral iron will fail in these conditions. 2
• Do not administer IV iron during active infection, as iron supplementation may promote bacterial growth and inflammation. 3