Products
In many countries, injection solutions containing ferric carboxymaltose (Ferinject, 2007), ferrous sucrose (Venofer, 1949), ferumoxytol (Rienso, 2012), and ferric derisomaltose (ferric isomaltoside, Monofer, 2019) are commercially available. In other countries, other products with different compositions are available, for example, ferrous sodium gluconate. Iron dextrans are rarely used anymore because of the risk for severe allergic reactions.
Structure and properties
Iron cannot be injected directly and freely in solution into the bloodstream because severe toxic reactions occur. Therefore, iron-carbohydrate complexes are used today. These complexes allow the controlled release of iron by being taken up and degraded by macrophages. The iron released in the cells is passed to ferritin and transferrin and utilized by the body. Ferric carboxymaltose is a macromolecular complex of ferric hydroxide and carboxymaltose, ferrous sucrose (= iron sucrose) is a complex of ferric hydroxide and sucrose, i.e. household sugar. Ferric derisomaltose (ferric isomaltoside ) is composed of ferric atoms and derisomaltose pentamers.
Effects
The supplied iron (ATC B03AC01, ATC B03AC02) substitutes the amount of iron lacking in the body. On the one hand, it is used to build hemoglobin and thus red blood cells, myoglobin, and enzymes, and on the other hand, it is stored in the liver, for example. A deficit can thus be quickly compensated.
Indications
Iron infusions are approved as a 2nd-line agent for the treatment of iron deficiency if oral administration is not sufficiently effective or not feasible. This is the case, for example, when oral drugs cause adverse effects, compliance with therapy is insufficient, or inflammatory bowel disease is present. Oral treatment has several disadvantages. These include poor absorption, long duration of therapy, the need for daily dosing, drug-drug interactions, and possible adverse effects in the digestive tract. Ferumoxytol should be administered only in the presence of chronic kidney disease.
Dosage
According to the SmPC. The amount of iron is determined individually and adjusted to the deficiency. Smaller doses may be given as slow intravenous injections; larger doses are given diluted with physiological saline as an intravenous infusion. Iron should not be injected subcutaneously or intramuscularly. Patients must be monitored carefully during and 30 minutes after administration because of the potential for hypersensitivity reactions.
Contraindications
Intravenous iron is contraindicated in hypersensitivity, anemia without confirmed iron deficiency (eg, vitamin B12 deficiency), iron overload, and during the first trimester of pregnancy. For complete precautions, see the drug label.
Interactions
Iron infusions should not be combined with oral iron.
Adverse effects
The most common possible adverse effects include headache, dizziness, rash, injection site reactions, phlebitis, metallic taste, nausea, abdominal pain, constipation, diarrhea, and joint pain. Hypersensitivity reactions up to and including anaphylaxis may occur, especially with the iron dextrans (off label). However, they are possible with all intravenous iron preparations. To prevent them, the precautionary measures in the technical information should be observed. Agent of 1st choice for treatment is adrenaline.
