A Retrospective Comparison of Adverse Reaction Rates with the Use of Three Intravenous Iron Formulations: A Single Center Experience.

Iron deficiency anemia is the most common hematology problem encountered in clinical practice. Oral iron is first line therapy, however successful treatment of iron deficiency often involves the use of parenteral formulations of iron. Before the 1990s, the only available and approved parenteral iron formulation was iron dextran which had a rare but definite association with fatal anaphylactic reactions and was all but abandoned by many practitioners. Since the late 1990s the US Food and Drug Administration has approved 3 new and ‘safer’ iron formulations: iron sucrose, ferric gluconate and most recently ferumoxytol. Besides ferumoxytol, the other formulations are roughly equivalent in cost.

To compare the adverse reaction rates associated with 3 formulations of parental iron (iron dextran, iron sucrose and ferric gluconate) currently in use at our center.

We reviewed the medical records, nursing documentation and pharmacy records of patients who were treated with parenteral iron at our center over a 2 year period (April 2008 – March 2010). A likelihood ratio chi-square test for comparison was calculated using SAS 9.2 statistical software.

Between April 2008 and March 2010, 510 patients received intravenous iron at our institution and all 510 patients’ charts were reviewed. 59% (302) of patients received ferric gluconate; 23% (116) received iron dextran and 18% (92) received iron sucrose. The overall reaction rate with iron infusions was 2%; 1.3% with ferric gluconate, 1.7% with iron dextran and 4.4% with iron sucrose. Reactions included facial flushing, chest tightness/pain, circumoral paresthesia, arm redness and swelling (in the absence of infusion infiltration) and lightheadedness. No respiratory compromise or anaphylactic reactions occurred and there were no deaths. Using the likelihood ratio chi-square test, these rates were not statistically different (p = 0.25).

Based on this single center experience, intravenous iron therapy is safe; iron dextran being just as safe as ferric gluconate and iron sucrose. Though iron sucrose was the least frequently used formulation and had a proportionately higher rate of adverse reactions, the difference was not statistically significant.

The use of iron dextran and iron sucrose allows for fewer clinic visits, is more convenient for the patient and results in lower total costs of therapy than ferric gluconate and we encourage their use for this reason. On the other hand, ferric gluconate was particularly well tolerated. Too few events occurred in this analysis to show a difference in the severity of reactions between the therapies. A larger study may show a cluster of more severe reactions to be associated with a specific iron formulation and would further influence decision-making of which iron formulations to use. In the immediate future, we will use our collated data to compare the effectiveness (success of iron repletion achieved) with each parenteral iron formulation to serve as an additional factor in the informed choice of treatment with a parenteral iron formulation.

No relevant conflicts of interest to declare.