[Iron deficiency and iron deficiency anemia].

Iron excretion from the body is minimal due to lack of an active excretion mechanism, and absorption is limited as well, making iron metabolism a semi-closed system. However, loss of iron-containing red blood cells through persistent gastrointestinal or gynecological bleeding depletes iron stores. If the bleeding progresses further, iron stores become insufficient for erythropoiesis, leading to iron deficiency anemia (IDA). IDA accounts for approximately 70% of all anemia cases. Furthermore, it is increasingly recognized that iron deficiency causes various symptoms even in the absence of anemia. Recent research has also revealed that iron-related tests are being underutilized in diagnosis and treatment. In recent years, ferric citrate hydrate has been added as a new oral iron preparation, along with ferric carboxymaltose and ferric derisomaltose as new intravenous options. Multiple clinical trials conducted in Japan have expanded the body of evidence. Alongside established agents, iron preparations are contributing to IDA treatment across a broad range of clinical areas.