What is the indication for intravenous (IV) iron therapy?

From the Guidelines

Intravenous (IV) iron is indicated for patients with iron deficiency anemia who cannot tolerate oral iron or when oral iron supplementation is ineffective, and formulations that can replace iron deficits with 1 to 2 infusions are preferred. This recommendation is based on the most recent and highest quality study available, which suggests that IV iron should be used when oral iron is not effective or tolerated 1. The study also highlights the importance of monitoring patients during infusion for potential adverse reactions, including hypersensitivity reactions, which are rare but can be serious.

Key Points to Consider

• IV iron is used to correct iron deficiency when oral iron supplements are ineffective, poorly tolerated, or when rapid iron repletion is needed 1.
• Common IV iron formulations include iron sucrose, ferric carboxymaltose, ferumoxytol, and iron dextran, with typical dosing varying by formulation 1.
• Treatment is indicated for patients with iron deficiency anemia who cannot take oral iron due to gastrointestinal side effects, malabsorption disorders, ongoing blood loss, or when rapid correction is necessary 1.
• Before administering IV iron, ferritin, transferrin saturation, and hemoglobin levels should be checked to confirm iron deficiency 1.
• Patients should be monitored during infusion for potential adverse reactions, including hypersensitivity reactions, which are rare but can be serious 1.

Best Practice Advice

According to the most recent study, IV iron formulations that can replace iron deficits with 1 or 2 infusions are preferred over those that require more than 2 infusions 1. This approach allows for faster correction of deficiency and improved hemoglobin levels compared to oral supplementation. Additionally, the study suggests that being truly allergic to IV iron is very rare, and most reactions are complement activation–related pseudo-allergy, which can be managed by stopping the infusion and restarting at a slower rate or using corticosteroids if necessary 1.

From the FDA Drug Label

Injectafer is indicated for the treatment of: • iron deficiency anemia (IDA) in: adult and pediatric patients 1 year of age and older who have either intolerance or an unsatisfactory response to oral iron. • iron deficiency in adult patients with heart failure and New York Heart Association class II/III to improve exercise capacity.

The recommended dosage of IV iron (ferric carboxymaltose) is:

• For patients weighing 50 kg or more: 750 mg intravenously in two doses separated by at least 7 days for a total cumulative dose of 1,500 mg of iron per course
• For adult patients: 15 mg/kg body weight up to a maximum of 1,000 mg intravenously may be administered as a single-dose per course
• For patients weighing less than 50 kg: 15 mg/kg body weight intravenously in two doses separated by at least 7 days per course 2

From the Research

IV Iron Therapy

• IV iron supplementation is a more effective and better-tolerated treatment for iron deficiency anemia compared to oral iron supplementation, especially in patients with underlying Inflammatory Bowel Disease (IBD) or malignancy 3.
• IV iron preparations can facilitate rapid iron repletion in one or two doses, making them suitable for patients with absolute iron deficiency and functional iron deficiency 4.
• Modern IV iron formulations have an excellent overall safety profile, but potential adverse effects such as skin staining, infusion-related reactions, and hypophosphataemia have been described 5.

Desensitization Protocols

• A novel eleven-step desensitization protocol for ferric carboxymaltose has been developed for patients with a history of anaphylaxis to IV iron and iron deficiency anemia, which was well-tolerated without any adverse reactions 3.
• A one-bag 8-step ferric carboxymaltose desensitization protocol has been successfully applied to patients with a history of hypersensitivity reactions to iron preparations, allowing for safe IV iron replacement 6.

Indications and Administration

• IV iron therapy is indicated for the treatment of iron deficiency when oral preparations are ineffective or cannot be used, and has applicability in a wide range of clinical contexts, including chronic inflammatory conditions, perioperative settings, and disorders associated with chronic blood loss 4.
• IV iron preparations can be infused at different doses and allow correction of total iron deficit with single or repeated doses in 1-2 weeks depending on the specific formulation 7.

Safety and Side Effects

• All iron preparations are associated with a risk of severe infusion reactions, but the risk of moderate to severe infusion reactions is comparable among all modern preparations, affecting <1% of patients 7.
• Hypophosphataemia is a potential complication of IV iron therapy, particularly with ferric carboxymaltose, which can cause severe and potentially irreversible clinical complications such as bone pain, osteomalacia, and fractures 7.