From the Guidelines
Intravenous (IV) iron is indicated for iron deficiency anemia when oral iron is ineffective, poorly tolerated, or contraindicated, as stated in the most recent guideline by the American Gastroenterological Association (AGA) in 2024 1.
Indications for IV Iron
The specific indications for IV iron include:
- Malabsorption disorders (celiac disease, inflammatory bowel disease, gastric bypass)
- Ongoing blood loss exceeding oral iron absorption capacity
- Severe anemia (hemoglobin <7 g/dL) requiring rapid correction
- Chronic kidney disease (especially in patients on hemodialysis)
- Heart failure
- Documented intolerance to oral iron preparations
Comparison of IV and Oral Iron
Oral iron remains first-line therapy for most patients with uncomplicated iron deficiency anemia due to its safety, low cost, and convenience. However, IV iron works faster than oral iron because it bypasses intestinal absorption limitations and delivers iron directly to transferrin and the reticuloendothelial system, allowing for more rapid erythropoiesis, as noted in a study published in 2019 1.
IV Iron Formulations
Common IV iron formulations include iron sucrose (Venofer), ferric gluconate (Ferrlecit), ferric carboxymaltose (Injectafer), and iron dextran (INFeD). The choice of IV iron formulation depends on patient and doctor preferences, formulation availability, cost, and comorbidities, as stated in a study published in 2017 1.
Safety and Efficacy
IV iron is generally safe and effective, but it carries small risks of infusion reactions and requires healthcare facility administration. The risk of iron overload in patients who are chronically bleeding is intrinsically low, as noted in a study published in 2015 1.
Treatment Duration
Treatment with IV iron should continue for 3-6 months after hemoglobin normalization to replenish iron stores, as recommended by the AGA in 2024 1.
Key Points
- IV iron is indicated for iron deficiency anemia when oral iron is ineffective, poorly tolerated, or contraindicated
- Specific indications for IV iron include malabsorption disorders, ongoing blood loss, severe anemia, chronic kidney disease, heart failure, and documented intolerance to oral iron preparations
- IV iron works faster than oral iron and delivers iron directly to transferrin and the reticuloendothelial system
- Common IV iron formulations include iron sucrose, ferric gluconate, ferric carboxymaltose, and iron dextran
- IV iron is generally safe and effective, but carries small risks of infusion reactions and requires healthcare facility administration.
From the FDA Drug Label
1 INDICATIONS AND USAGE
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.
- adult patients who have non-dialysis dependent chronic kidney disease. • iron deficiency in adult patients with heart failure and New York Heart Association class II/III to improve exercise capacity.
The indications for intravenous (IV) iron versus oral iron are as follows:
- IV iron is indicated for:
- Adult and pediatric patients (1 year of age and older) with iron deficiency anemia who have either intolerance or an unsatisfactory response to oral iron.
- Adult patients with non-dialysis dependent chronic kidney disease.
- Adult patients with heart failure and New York Heart Association class II/III to improve exercise capacity.
- Oral iron is not explicitly indicated in the provided drug label, but it is mentioned as a comparison for IV iron in patients who have had an unsatisfactory response or are intolerant to oral iron. 2
From the Research
Indications for IV Iron Versus Oral Iron
The choice between intravenous (IV) iron and oral iron for the treatment of iron deficiency anemia depends on several factors, including the severity of the anemia, the presence of chronic kidney disease, and the patient's ability to tolerate oral iron supplements.
- Chronic Kidney Disease (CKD): In patients with CKD, IV iron is often preferred due to its ability to rapidly replenish iron stores and improve hemoglobin levels 3. Oral iron supplements may be poorly absorbed in these patients, and IV iron can help avoid the gastrointestinal side effects associated with oral iron.
- Erythropoiesis-Stimulating Agents (ESAs): Patients receiving ESAs for anemia may benefit from IV iron supplementation, as it can help increase hemoglobin levels and reduce the need for ESAs 3, 4.
- Gastrointestinal Side Effects: Patients who experience gastrointestinal side effects with oral iron supplements, such as nausea, vomiting, or constipation, may prefer IV iron therapy 5, 6.
- Compliance: Patients who have difficulty adhering to oral iron supplements due to swallowing problems or forgetfulness may benefit from IV iron therapy 5.
- Iron Deficiency Anemia: In patients with iron deficiency anemia, oral iron supplements are often the first-line treatment due to their ease of use and low cost 6. However, IV iron may be preferred in patients who do not respond to oral iron or who have severe anemia.
Comparison of IV Iron and Oral Iron
Studies have compared the efficacy and safety of IV iron and oral iron in patients with iron deficiency anemia.
- Efficacy: IV iron has been shown to be more effective than oral iron in increasing hemoglobin levels and improving iron stores in patients with CKD and anemia 3, 4.
- Safety: IV iron has been associated with a lower risk of gastrointestinal side effects compared to oral iron, but may carry a risk of allergic reactions or anaphylaxis 3, 4.
- Patient Preference: A patient-preference study found that the majority of patients preferred IV iron therapy due to its ease of use and lower risk of side effects 5.
Alternate-Day Oral Iron Therapy
Alternate-day oral iron therapy has been proposed as a way to reduce the gastrointestinal side effects associated with daily oral iron supplements.
- Efficacy: A systematic review found that alternate-day oral iron therapy was as effective as daily oral iron therapy in increasing hemoglobin levels and improving iron stores 7.
- Side Effects: Alternate-day oral iron therapy was associated with a lower risk of gastrointestinal side effects, such as nausea and constipation, compared to daily oral iron therapy 7.