Pharmacology
Pharmacodynamics
Iron is necessary for maintaining optimal health, especially for the formation of red blood cells, which carry oxygen throughout the body. An iron deficiency means that the body cannot produce enough healthy red blood cells. Iron deficiency anemia occurs when the body's iron stores fall to too low a level and the stored iron is insufficient to support normal red blood cell production. Insufficient iron in the diet, impaired iron absorption, bleeding, pregnancy, or iron loss through the urine can lead to iron deficiency. Symptoms of iron deficiency anemia include fatigue, shortness of breath, palpitations, dizziness and headaches. Taking iron in the form of dietary supplements, such as ferrous sulfate, allows iron levels to rise more rapidly when dietary intake and iron stores are inadequate.
Pharmacokinetics
Orally administered iron has widely varying bioavailability depending on circumstances, including the valence of the iron (Fe2+ or Fe3+), dietary intake, and degree of iron deficiency. Bivalent iron is more soluble and therefore usually has a higher bioavailability than trivalent iron (Fe3+). Absorption occurs mainly in the small intestine, particularly in the duodenum and proximal jejunum. Approximately 60% of the iron is absorbed into the erythrocytes. The rest of the iron is found in muscle tissue (as part of myoglobin) and in a variety of different enzymes, as well as in its storage form, ferritin.