Clinical update: Intravenous iron for anaemia.
A Comment article in today's Lancet discusses the use of parenteral iron in patients with iron-deficiency anaemia. The authors assert that this form of therapy is underused, due to concerns over the toxicity of one particular preparation; they consider that using current preparations and appropriate regimens it is safe and effective. Parenteral iron has been considered dangerous and a therapy of last resort because the only preparation available for many years, high-molecular-weight iron dextran, was occasionally associated with anaphylactic reactions. There are now four parenteral iron preparations available, the other three - low-molecular-weight iron dextran, and two iron salts, ferric gluconate and iron saccharate - being associated with a much lower incidence of adverse effects.
The authors discuss the situations in which parenteral iron is appropriate, and how these may affect the choice of preparation and regimen. Iron dextran, preferably the low-molecular-weight form, may be given as a total dose infusion: a test dose is usually specified, however the authors report no untoward events with experience of over 20,000 doses and question the need for this if the low-molecular-weight form is used. This and the iron salts can be given as short infusions containing 100 to 400mg for patients receiving cyclical therapy. IM use is not recommended - it is no safer and has significant local toxicity at the injection site.
Overall, the authors conclude that intravenous iron is a misunderstood and under-used tool in the treatment of iron-deficiency anaemia; this is due at least in part to misinformation and misinterpretation of the data on serious adverse events. If the high-molecular-weight dextran form is excluded, it is associated with no substantially increased risk.
Lancet 2007; 369: 1502-4 (Comment; link to full text, available to subscribers only)