Intravenous iron in inflammatory bowel disease
Authors: Michael Auerbach
Journal: American Journal of Hematology (2014)

This is the third in a series of short articles concerning iron deficiency and the role of intravenous (IV) iron. Iron deficiency anemia is nearly ubiquitous in this population 1 and it is the opinion of many key opinion leaders in the field that failure to routinely replace iron intravenously represents and unmet clinical need. In those with uncomplicated iron deficiency without underlying inflammatory disorders which lead to iron restricted erythropoiesis due to hepcidin upregulation, oral iron is effective and inexpensive. Unfortunately, estimates that 70% of those to whom it is prescribed report significant gastrointestinal perturbation, results in significant nonadherence to therapy. Evidence suggests oral iron causes severe adverse invents when inflammatory bowel disease is present and worsens the underlying pathology 2-4. While some gastroenterologists continue to extol the virtues of low doses of oral iron, even if well tolerated in subjects with quiescent disease, a year of therapy is required to replace stores. European and American guidelines differ. European guidelines state that the preferred route of iron supplementation in inflammatory bowel disease (IBD) is IV, even though some patients will respond to oral iron. IV iron is more effective and better tolerated and improves the quality of life to a greater extent than oral iron supplementation (Grade A) 2. Absolute indications for IV iron include severe anemia (Hgb <10 g/dl), intolerance of or inappropriate response to oral iron, severe intestinal disease acuity, and concomitant therapy with an erythropoiesis agent or patient preference. Oral iron supplements can be used if absolute indications for IV iron therapy are not met. If oral iron is used, the response and tolerance should be monitored and treatment changed to IV as necessary (Grade C). Because side effects of oral iron are dose related and because its absorption and efficacy are no greater when high doses are used, no more than 100 mg of elemental iron daily should be prescribed (Grade C). American guidelines state, “oral formulations are more convenient and less expensive and may be used as a first-line option for patients whose IBD activity and anemia are mild” 5. The medical literature is rife with prospective comparative evidence demonstrating superiority of IV iron over oral iron in both efficacy and toxicity. Recent publications support this view 6-8. With the advent of four new formulations which allow safe and rapid complete replacement dosing in 15–60 min, the failure to routinely administer IV iron to anemic patients with inflammatory bowel disease may represent another unmet clinical need. A recent publication demonstrated that not only does a 15 min infusion of ferric carboxymaltose correct anemia but prevents recurrence of anemia in patients with inflammatory bowel disease 9. Similar evidence of efficacy has been published with low molecular weight iron dextran 10, 11 and ferumoxytol 12. Although it remains reasonable to try oral iron in those without active disease, considering the litany of gastrointestinal perturbations present in inflammatory bowel disease, even in remission, perhaps it is time for American gastroenterologists to become more congruent with their European colleagues. Michael Auerbach* Clinical Professor of Medicine, Georgetown University School of Medicine Auerbach Hematology and Oncology, Baltimore, Maryland 21237