Anagrelide is primarily used to treat thrombocythemia, a condition characterized by an excessive production of platelets in the blood. By inhibiting the maturation of megakaryocytes, it effectively reduces platelet counts, thereby lowering the risk of thrombosis and bleeding complications associated with high platelet levels. It is particularly beneficial for patients with essential thrombocythemia who are at risk of developing blood clots or have a history of thrombotic events. The medication is often prescribed when other treatments, such as hydroxyurea, are not suitable or effective. Regular monitoring of blood counts is essential during treatment to ensure optimal dosing and to minimize potential side effects.