From the Guidelines
Iron supplements that are specifically designed to be released only in the liver typically use a targeted drug delivery system known as parenteral iron therapy, particularly iron carboxymaltose or iron dextran, as evidenced by recent studies 1. These intravenous iron formulations are administered directly into the bloodstream and are then taken up by the reticuloendothelial system in the liver, where they are processed and stored as ferritin. The key benefits of this approach include:
- Rapid correction of iron deficiency
- Avoidance of common side effects of oral iron such as constipation, nausea, and abdominal discomfort
- Targeted delivery to the liver, where the iron is processed and stored The liver-specific release occurs because these complex iron molecules are too large to be filtered by the kidneys and are instead recognized by macrophages in the liver, which break down the carbohydrate shell and incorporate the iron into the body's iron stores. As noted in a study published in the Journal of the National Comprehensive Cancer Network 1, intravenous iron is superior to oral iron, particularly in patients with chemotherapy-induced anemia. In terms of specific formulations, iron dextran is a commonly used option, with studies such as the one published in the American Journal of Kidney Diseases 1 highlighting its efficacy and safety profile. However, it is essential to note that the most recent and highest quality study 1 should be prioritized when making a definitive recommendation, and this study supports the use of parenteral iron therapy for targeted delivery to the liver.
From the Research
Iron Delivery Mechanism
The process of delivering iron supplements that are only released in the liver is not explicitly described in the provided studies. However, the studies discuss the use of ferric carboxymaltose, an intravenous iron preparation, for the treatment of iron deficiency anemia.
Key Characteristics of Ferric Carboxymaltose
- Ferric carboxymaltose is a macromolecular ferric hydroxide carbohydrate complex that allows for controlled delivery of iron within the cells of the reticuloendothelial system 2
- It is distributed primarily to the bone marrow (approximately 80%) and also to the liver and spleen 2
- Ferric carboxymaltose is rapidly cleared from the circulation and results in transient elevations in serum iron, serum ferritin, and transferrin saturation 2
Efficacy and Safety of Ferric Carboxymaltose
- Ferric carboxymaltose is effective in replenishing iron stores and correcting anemia in patients with iron-deficiency anemia 2, 3, 4
- It is generally well tolerated, with a low risk of hypersensitivity reactions 2, 5, 4
- The most common laboratory abnormality seen in ferric carboxymaltose recipients is transient, asymptomatic hypophosphataemia 4
Administration of Ferric Carboxymaltose
- Ferric carboxymaltose can be administered in high single doses (up to 1000 mg of iron) in a short time frame (15 minutes) 2, 3, 4
- It can be used to treat iron deficiency anemia in various populations, including patients with chronic kidney disease, inflammatory bowel disease, or heavy uterine bleeding 2, 4