Severe hypophosphataemia after intravenous iron administration

Area of Science:

• Internal Medicine
• Nephrology
• Endocrinology

Background:

• Intravenous (IV) iron administration is increasingly favored over oral iron due to superior efficacy and fewer gastrointestinal side effects.
• Previous studies indicated that IV ferric carboxymaltose can cause asymptomatic, transient decreases in serum phosphate levels.

Observation:

• This report details four cases of severe, symptomatic hypophosphatemia following IV iron administration for iron deficiency anemia secondary to heavy menstrual bleeding.
• In three of the four cases, patients had pre-existing conditions affecting phosphate homeostasis, including secondary and tertiary hyperparathyroidism.
• One patient had no identifiable risk factors for phosphate dysregulation prior to IV iron therapy.

Findings:

• Severe and symptomatic hypophosphatemia can be a significant adverse event associated with IV iron therapy.
• This condition can be prolonged, persisting for months after iron administration.
• Patients with existing phosphate imbalances, such as hyperparathyroidism or vitamin D deficiency, face a heightened risk.

Implications:

• Clinicians should be vigilant for symptomatic hypophosphatemia in patients receiving IV iron, particularly those with pre-existing phosphate-regulating disorders.
• Monitoring phosphate levels and considering risk factors before initiating IV iron therapy is crucial.
• Further research is warranted to elucidate the precise mechanisms and optimize management strategies for IV iron-induced hypophosphatemia.