Polysaccharide iron complex ingestions reported to a regional poison centre: a retrospective review 2011-2023

Polysaccharide iron complex is a widely used iron supplement with a high elemental iron content. Despite a reported lethal dose 50 (LD50) significantly higher for polysaccharide iron complex than for iron salts (ferrous fumarate, ferrous sulfate, ferrous gluconate), commonly used poison centre reference databases such as Micromedex^® and Toxinz^® do not differentiate between polysaccharide iron complex and other iron formulations for the emergency department referral threshold (40 mg/kg elemental iron). The purpose of this study is to review polysaccharide iron complex exposures reported to a poison centre for clinical outcomes.

We performed a retrospective review of polysaccharide iron complex calls to a regional poison centre between 2011 and 2023. The poison centre electronic database Visual Dotlab was searched for records encoded with America's Poison Centers^® Generic Code^® "23000" as well as for substances documented as: "Iron", "Polysaccharide", and "Feramax^®". Cases with a co-ingestion of other iron salts were excluded. Records were individually reviewed for details of ingestion amount, symptoms, management recommendations, medical outcome, and serum iron concentrations.

The search yielded 219 cases of polysaccharide iron complex ingestions. The median elemental iron ingestion amount was 300 mg (range 45-14,250 mg; IQR 150-750 mg) or 12.7 mg/kg (n = 193) when patient weight was available (range 1.7-225 mg/kg; IQR 6-26.4 mg/kg). The majority (161/219) of the cases were below the 40 mg/kg threshold, with 32/219 above that threshold. All 170 unintentional ingestions and 41/49 (84%) intentional ingestions sustained "No" or "Minor" effects despite intentional ingestions having significantly higher ingestion amounts. "Moderate" and "Major" effects were only documented in intentional ingestions with co-ingestants. Serum iron concentrations were recorded for 39 cases, with the highest at 75 µmol/L (56.6 mg/kg ingestion), and 70 µmol/L (225 mg/kg ingestion); both were polyingestions with suicide intent. None of the patients required treatment with deferoxamine based on serum iron concentrations or symptoms.

This study demonstrates that unintentional polysaccharide iron complex ingestions are benign, with larger ingestions (up to 225 mg/kg), including intentional ingestions, having minimal toxicity.

Polysaccharide iron complex appears to have low toxicity, suggesting that poison centres may consider modifying recommendations to reflect the lower toxicity potential for polysaccharide iron complex ingestions.