An intravenous (IV) iron infusion delivers iron directly into the bloodstream. This method treats iron deficiency when oral supplements are ineffective, not tolerated, or when a rapid increase in iron levels is required. Administering iron directly into a vein efficiently replenishes the body’s iron stores, bypassing gastrointestinal absorption issues. This ensures iron is readily available for needs like red blood cell production.
The Iron Compounds Used
IV iron infusions use complex iron compounds, not elemental iron, engineered for safe delivery. These compounds have an iron core surrounded by a carbohydrate shell, which controls iron release and minimizes toxicity. Several types of intravenous iron preparations are currently in use, each with distinct chemical structures and characteristics.
Iron sucrose is a common preparation, featuring a polynuclear iron (III)-hydroxide core stabilized by sucrose molecules. This formulation is often administered in multiple doses.
Ferric carboxymaltose is another widely used compound, characterized by a ferric iron core complexed with a carboxymaltose polymer. It allows for larger doses over a shorter period, making it a convenient option for patients.
Iron dextran is an older, yet utilized, preparation consisting of ferric hydroxide complexed with dextran. Modern low molecular weight formulations have a lower risk of adverse reactions compared to earlier versions.
Ferumoxytol is composed of superparamagnetic iron oxide nanoparticles encapsulated within a semi-synthetic carbohydrate shell, polyglucose sorbitol carboxymethylether. This unique structure enables controlled iron release and can be administered relatively quickly.
Components of the Infusion Solution
Beyond the active iron compound, the complete infusion solution contains other components for safe and stable delivery into the bloodstream. The iron compound is typically dissolved or suspended within a sterile carrier solution. The most common carrier for diluting intravenous iron preparations is 0.9% sodium chloride, often called normal saline.
A sterile, isotonic solution like normal saline maintains compatibility with body fluids and prevents cellular damage. Infusion solutions are formulated to be free from active pharmaceutical ingredients other than the iron compound. Some formulations include minor inactive ingredients, such as sodium hydroxide or hydrochloric acid, which are used to adjust the pH for stability and administration.
How Infusions Are Prepared and Administered
Preparing an IV iron infusion involves diluting the concentrated iron compound in a larger volume of sterile solution just prior to administration. This dilution step ensures gradual iron delivery into the bloodstream for patient safety and comfort. Normal saline is the standard diluent.
Once prepared, the iron solution is administered directly into a patient’s vein through an IV line. A healthcare professional, typically a nurse, inserts a small catheter into a vein, often in the arm or hand, and connects it to the IV bag. The solution drips steadily into the vein over a specific period, ranging from 15 minutes to several hours, depending on the iron compound and total dose. This procedure occurs in a medical setting, such as a hospital or clinic, where the patient’s vital signs can be monitored throughout the infusion.