Purpose of review: Anemia and iron deficiency are the most common extraintestinal complications of inflammatory bowel diseases (IBDs) and are often undertreated. We review the evidence on intravenous (i.v.) iron overcoming the limitations of oral iron in IBD.
Recent findings: Recent reports demonstrate that i.v. iron is at least as effective, quicker, and better tolerated than oral iron. Moreover, experimental data confirm that oral and parenteral iron have divergent effects on intestinal mucosa: oral iron severely increasing inflammation. Observational and randomized studies prove that i.v. iron is not only effective but also well tolerated with no negative influence in the activity of IBD. A new formulation, iron carboxymaltose, which permits higher individual doses, has been shown more effective and less costly than standard iron sucrose. Another formulation, iron isomaltoside, shows promising in in-vitro and small clinical studies, but data from large trials are not available yet.
Summary: Oral iron is not an ideal option for treating anemia and iron deficiency in IBD. i.v. iron should be preferred at least in five scenarios: intolerance to oral iron, severe anemia, failure of oral therapy, need for a quick recovery, and use of erythropoietin. Direct evidence in IBD patients not only confirms the effectiveness of i.v. iron, but also demonstrates that new, more convenient preparations probably will become the standard in the near future.