With regard to the cause of iron deficiency, causal therapy should follow appropriate diagnosis, and appropriate iron substitutionshould also be initiated in cases of manifest iron deficiency (Herold 2022).
Iron substitution should be administered orally as initial therapy. Only divalent iron should be used for oral treatment, since the intestine can only absorb 10-20% of it (Herold 2022).
Bivalent iron is mainly absorbed in the duodenum and upper jejunum. Animal iron is already present as divalent Fe ++, trivalent iron ions from plant foods must first be reduced to divalent ions in the apical cell membrane (Behnisch 2021).
Dosage recommendation:
Iron lozenges e.g. on an empty stomach 1 x 100 mg Fe (II) / d or every 2nd day. With the 2-day administration, there is better tolerance and, due to the decrease in hepcidin, better absorption (Herold 2022).
Adverse effects:
- Gastrointestinal discomfort in the form of nausea, vomiting, constipation (Kasper 2015).
Duration of use:
The target value for ferritin is about 100 µg / l. Once this is reached, substitution should continue for another period of 3 - 6 months (Herold 2022).
Laboratory Controls:
Reticulocytes and Hb increase after only 1 week (Herold 2022), if the iron deficiency is severe. Serum ferritin should be checked after about 3 months (Behnisch 2021).
Indication:
The indication for parenteral iron substitution is in patients who
- cannot tolerate oral iron
- whose need is quite acute
- who are in constant need of iron (Kasper 2015)
- suffer from gastrointestinal diseases
- in severe renal insufficiency with large iron depots, but which cannot be mobilized (Wick 2013)
- In certain palliative situations, such as severe heart failure, (Lundgren 2018).
Here, parenteral iron administration in iron deficiency can relieve symptoms even in the absence of anemia (Lundgren 2018).
In recent years, parenteral administration has increased dramatically (Kasper 2015).
Iron from dextran-free high molecular weight stable complexes should be used for parenteral administration. Mixed injections should be avoided at all costs (Herold 2022).
Dosage Recommendation:
Iron (III) carboxymaltose such as Ferinject should be injected as an infusion up to 1,000 mg 1 x / week.
For iron (III) derisomaltose such as MonoFer, the maximum single dose is 20 mg / kg .
For iron (III) sodium gluconate complex such as Ferrlecit, the maximum single dose is 62.5 mg.
In the case of iron (III) hydroxide-sucrose complex such as Venofer, the maximum single dose that can be injected is 200-500 mg (Herold 2022).
The respective manufacturer's instructions should always be followed.
The injection should be administered slowly (follow the manufacturer's exact time instructions). A short infusion in 100 ml NaCl has been found to be best (Herold 2022).
Duration of use:
Total requirement is based on product information. Normalization of hemoglobin is the surest indicator of adequate substitution.
Serum ferritin should reach about 100 µg / l and transferrin saturation (TSAT) should be between 20 - 45% (Herold 2022). In any case, an increase in transferrin saturation to > 50 % should be prevented. If this persists for a long time, it is an indication of iron overload of the tissue. Since iron is toxic to cells, this condition should be avoided at all costs (Kasper 2015).
Laboratory Checks:
The earliest laboratory control is recommended 8 - 12 weeks after the last iron administration, as false positive values are indicated before that (Herold 2022).
Iron supplementation can also be given as:
- Erythrocyte transfusion (Kasper 2015).
- Erythropoiesis-stimulating agents (Metzgeroth 2015).
For more details see iron deficiency anemia.