[Iron deficiency anemia and newly available iron preparations].

The body does not possess an active export system for iron. Therefore, the amount of iron uptake is usually small; iron metabolism in the body should be considered a "semi-closed system." However, iron needed for erythropoiesis can be lacking in the case of continuous bleeding, and thus, iron deficiency anemia (IDA) would occur. IDA is the most common form of anemia; approximately 70% of anemia is IDA. Therefore, upper and lower endoscopies or gynecological procedures should be used to treat bleeding sites; in addition, the small intestine can now be widely observed and treated by double-balloon and capsule endoscopies. Iron replacement therapy for IDA is also important; however, oral iron administration frequently causes adverse events in the gastrointestinal tract, such as nausea and vomiting, making long-term oral iron administration difficult. Newly approved ferric citrate hydrate causes fewer adverse events for the gastrointestinal tract. For a long time, concerning intravenous (IV) iron formulation, saccharated ferric iron oxide has been the only available IV iron formulation in Japan. However, ferric carboxymaltose was recently approved, and administration at a dose of 500 mg/day can achieve a certain iron replacement with less administration. Thus, more effective treatment for patients with IDA might be achieved by these new procedures as well as oral and IV iron preparations.