True anaphylaxis is very rare, but complement-mediated infusion reactions may be seen in up to 1 in every 200 patients. Intravenous iron is being used more frequently to replete iron stores. In addition, many patients will not respond to oral iron due to their underlying illness. Oral iron is often poorly tolerated, with up to 70% or more of patients noting gastrointestinal issues this may affect adherence to therapy. As the adverse effects of iron deficiency are better recognized, the use of oral and intravenous iron has increased dramatically.
