Abstract
"Tired blood" is a common term used to describe anemia because of the association between fatigue, often the first sign of anemia, and the idea that it has "something to do with blood." Today, millions of people have diagnosed anemia, and millions more with chronic diseases are at risk for developing anemia. Anemia is not a specific disease; rather, it is an indication that something has either disturbed the maturation of essential red blood cells or interfered with the oxygen carry capacity of red cells. In this two-part series about tired blood, the etiology and pathophysiology of selected forms of anemia are discussed and pharmacotherapy designed to address the condition of anemia is identified. Part 1 addresses anemia related to red blood cell development, and Part 2 explores the physiology of hemoglobin-related anemia and inherited anemia.