Safety of Intravenous Iron Following Infusion Reactions

Where an ongoing requirement for intravenous iron replacement exists after an index infusion reaction, current recommendations are limited to expert opinion and isolated case reports.

To evaluate the safety of recommencing an infusion or subsequent rechallenge following an infusion reaction to intravenous iron.

Infusion reactions to intravenous iron occurring between January 1, 2010, and December 31, 2019, at a metropolitan health network were identified. Patient characteristics, reaction type (mild, moderate, or severe hypersensitivity, delayed, or Fishbane: transient flushing and truncal myalgias), and outcomes of recommencing the index infusion or subsequent rechallenge were examined.

Among 13,509 iron infusions, 195 infusion reactions occurred in 195 patients (1.4% of infusions). Recommencement of the index infusion (generally with a reduced infusion rate and premedication) was tolerated in 33 of 33 patients with Fishbane (20 of 20) or mild (9 of 9) and moderate (4 of 4) hypersensitivity reactions. Subsequent rechallenge (generally at standard infusion rates to an alternative formulation, ferric carboxymaltose) was successful in 68 of 69 patients with Fishbane (23 of 23), mild (26 of 26), moderate (16 of 17), and severe (3 of 3) hypersensitivity, or delayed (2 of 2) reactions. All 9 patients rechallenged to the original formulation (iron polymaltose) completed the infusion.

Following an infusion reaction to intravenous iron infusion, recommencement of the index infusion is safe for Fishbane or mild and moderate hypersensitivity reactions. Subsequent rechallenge to an alternative formulation is tolerated, including in severe hypersensitivity reactions (albeit based on limited numbers). Where alternative formulations are not available, rechallenge to the same formulation could be considered, depending on the risk-benefit profile.