What is the mechanism of action of Dexorange (iron supplement)?

Mechanism of Action of Dexorange (Iron Supplement)

Dexorange is an iron supplement that works by providing elemental iron to replenish depleted iron stores and support hemoglobin synthesis in patients with iron deficiency and iron deficiency anemia.

Iron Metabolism and Function

• Iron is an essential mineral with total body content averaging approximately 3.8g in men and 2.3g in women 1
• More than 80% of functional iron in the body is found in red blood cells as hemoglobin, with the remainder in myoglobin and intracellular respiratory enzymes 1
• Iron is stored primarily as ferritin and transported in blood by the protein transferrin 1

Components and Mechanism of Dexorange

Dexorange typically contains:

• Ferric ammonium citrate (iron component)
• Cyanocobalamin (vitamin B12)
• Folic acid

The mechanism of action involves:

1. Iron Absorption and Transport:

   • After oral administration, iron is absorbed in the duodenum and upper jejunum 1
   • Absorption is regulated based on body iron stores - increased when stores are low and decreased when sufficient 1
   • Iron bioavailability varies from less than 1% to greater than 50% depending on various factors 1

2. Incorporation into Hemoglobin:

   • Absorbed iron binds to transferrin for transport to bone marrow 2
   • In bone marrow, iron is incorporated into hemoglobin during erythropoiesis 1
   • This process helps correct anemia by increasing hemoglobin levels 1

3. Replenishment of Iron Stores:

   • Excess iron is stored as ferritin and hemosiderin primarily in the liver, spleen, and bone marrow 1, 2
   • These stores can be mobilized when needed for erythropoiesis 1

Factors Affecting Iron Absorption

• Enhancers of iron absorption: Vitamin C (included in many formulations), heme iron 1
• Inhibitors of iron absorption: Polyphenols, tannins (in tea), phytates (in bran), and calcium (in dairy products) 1
• Physiological factors: Iron absorption increases during pregnancy and in states of iron deficiency 1

Clinical Application

• Oral iron supplementation is recommended as first-line treatment for iron deficiency anemia when the gastrointestinal tract is functioning normally 1
• The goal of iron supplementation is to normalize hemoglobin levels and replenish iron stores 1
• An acceptable response is an increase in hemoglobin of at least 2g/dL within 4 weeks of treatment 1
• Treatment should continue for 3 months after correction of anemia to ensure replenishment of iron stores 1

Limitations and Considerations

• Oral iron supplements may cause gastrointestinal side effects including nausea, constipation, and diarrhea 1, 3
• Absorption may be impaired in conditions with inflammation due to increased hepcidin levels 1
• In cases of severe anemia, malabsorption, or intolerance to oral iron, intravenous iron preparations may be preferred 1

Monitoring

• After normalization of hemoglobin, monitoring should continue at 3-month intervals for 1 year, then after a further year 1
• Further oral iron should be given if hemoglobin or red cell indices fall below normal 1