Methemoglobinemia Following Intravenous Iron Treatment

Methemoglobin is an isoform of hemoglobin without oxygen carrying properties. Higher levels of methemoglobin may impact oxygen transport of the blood and increase the risk of tissue hypoxia. Methemoglobinemia has been reported as side effect of different drugs such as antibiotics or local anesthetics, but not after iron preparations. There is only one case report of increased levels of methemoglobin following intravenous iron therapy.

Patients with anemia due to iron deficiency can be treated with intravenous iron preparations such as ferric carboxymaltose or ferric derisomaltose. Anemia itself reduces oxygen transport of the blood, increasing the risk of tissue hypoxia due to methemoglobinemia in those patients.

This study aims to assess methemoglobinemia following treatment with intravenous iron in patients with anemia. The report will include case reports of patients with severe anemia who developed methemoglobinemia following treatment with ferric derisomaltose. Furthermore, methemoglobin levels are evaluated before and after intravenous iron administration in a cohort of adult patients with anemia who are scheduled to receive ferric carboxymaltose or ferric derisomaltose in routine care.

Inclusion criteria

for patients in the cohort study:

• anemia
• prescription of administration of intravenous iron (ferric carboxymaltose or ferric derisomaltose)

for patients in the case report:

• patients with severe anemia who developed methemoglobinemia following administration of ferric derisomaltose

Exclusion criteria

• declined consent
• known or suspected methemoglobinemia of genetic or other origin
• previous administration of intravenous iron within one week before study sampling.