Products
Iron is available in the form of tablets, capsules, chewable tablets, drops, as a syrup, direct granules and as a solution for injection, among others (selection). These are approved drugs and dietary supplements. It is also combined with folic acid, with vitamin C and with other vitamins and minerals fix. Some dosage forms are enteric-coated. The registered drugs usually contain much more iron than the supplements (e.g., 80 to 100 mg vs. 10 mg per unit). This article refers primarily to oral therapy. Iron is also administered intravenously; see Iron Infusions.
Structure and properties
Iron (ferrum, Fe, atomic number: 26) is a shiny, gray metal that belongs to the transition metals. It is the most abundant chemical element on Earth and was formed in stars by nuclear fusion. Pure iron rusts rapidly in air with water and oxygen, forming reddish-brown iron oxides and iron oxide hydroxides. Rust is ubiquitous in everyday life and also occurs on stones. The red color of the planet Mars comes from iron oxides (see also under redox reactions). Iron has a high melting point of 1538 °C. If carbon is added to the liquid metal, steel is produced which is much harder and more durable. The human body contains only a few grams of the trace element. In medicines and food supplements, iron is present in the form of divalent or trivalent salts (Fe2+ or Fe3+) or as organic complexes. Typical compounds include ferrous sulfate, ferric chloride, ferrous fumarate, and ferrous gluconate. Since divalent Fe2+ is better absorbed than trivalent Fe3+, iron is present in divalent form in most drugs.
Effects
Iron serves to substitute the missing trace element in the body. Among other things, it is found in heme, which is responsible for transporting oxygen in the hemoglobin of red blood cells and is also present in myoglobin. As a component of many enzymes, for example cytochromes, it also plays an important role in metabolism. Iron is absorbed irregularly and incompletely from the small intestine. Absorption is increased in the presence of iron deficiency.
Indications
For the prevention and treatment of iron deficiency and iron deficiency anemia. The drugs for therapy should be taken only when iron deficiency has been confirmed with appropriate laboratory analysis. The low-dose dietary supplements, on the other hand, can be administered even without a diagnosis.
Dosage
According to the SmPC. Oral preparations are usually taken fasting and at least one hour before or two hours after eating. Some medications may also be administered with food. If not well tolerated, iron may also be swallowed with or shortly after food. Oral therapy duration should be at least two months. Usually, several months are needed to compensate for a deficiency. The course and success of therapy is determined by laboratory analysis. Iron should not be overdosed. Daily requirement (nutrition): The daily requirement for adults is 10 mg or 15 mg depending on gender and age. The requirement is slightly higher during pregnancy and lactation.
Contraindications
Contraindications include:
- Hypersensitivity and intolerance
- Anemia without confirmed iron deficiency
- Iron overload (iron accumulation)
- Iron utilization disorders
- Severe liver and kidney disease
- Children, depending on the product
Full precautions can be found in the drug label.
Interactions
Iron may reduce the absorption of other drugs and thus their effectiveness. This is true, for example, of certain antibiotics such as the tetracyclines and quinolones, bisphosphonates, and thyroid hormones. Conversely, drugs can also reduce the absorption of iron, such as antacids and mineral supplements. An adequate time interval of at least two to three hours between intakes is recommended. Some foods can greatly reduce the absorption of iron, including tea, coffee, milk, eggs, cereals, and spinach. Oral iron should not be combined with iron infusions. Finally, iron may increase the mucosal irritant effects of other medications.
Adverse effects
The most common possible adverse effects include gastrointestinal disturbances such as abdominal pain, diarrhea, constipation, nausea, vomiting, and dyspepsia. Iron darkens the stool, but this is harmless and has no medical relevance. The gastrointestinal side effects can negatively impact adherence to therapy and lead to discontinuation. Iron can discolor teeth and cause ulceration of the oral mucosa. Therefore, the agents should not be kept in the mouth or sucked. Iron has mucosal irritant properties and should be taken only with caution in inflammatory diseases of the gastrointestinal tract or gastric and intestinal ulcers. For children, even a small overdose can be dangerous to life-threatening, for example in the case of accidental ingestion. Therefore, the preparations should be kept out of reach of children.
