Anagrelide is used to decrease the number of platelets (a type of blood cell that is needed to control bleeding) in the blood of patients who have a bone marrow disorder, in which the body makes too many of one or more types of blood cells, such as essential thrombocythemia (condition in which the body makes too many platelets) or polycythemia vera (condition in which the body makes too many red blood cells and sometimes too many platelets). Anagrelide is in a class of medications called platelet-reducing agents.