Indications Not all those affected will require treatment at presentation. People are usually split up into low and high risk for bleeding/blood clotting groups (based on their age, their medical history, their blood counts and their lifestyles), low risk individuals are usually treated with aspirin, whereas those at high risk are given hydroxycarbamide and/or other treatments that reduce platelet count (such as interferon-α and anagrelide). Agents Hydroxycarbamide, interferon-α and anagrelide can lower the platelet count. Low-dose aspirin is used to reduce the risk of blood clot formation unless the platelet count is very high, where there is a risk of bleeding from the disease, and hence this measure would be counter-productive as aspirin-use increases the risk of bleeding. The PT1 study compared hydroxyurea plus aspirin to anagrelide plus aspirin as initial therapy for<unk> . Hydroxyurea treated patients had a lower incidence of arterial thrombosis, lower incidence of severe bleeding and lower incidence of transformation to myelofibrosis, but the risk of venous thrombosis was higher with hydroxycarbamide than with anagrelide. It is unknown whether the results are applicable to all<unk>  patients. In people with symptomatic<unk>  and extremely high platelet counts (exceeding 1 million), plateletpheresis can be used to remove platelets from the blood to reduce the risk of thrombosis.
Essential thrombocythemia
Refractory cytopenia of childhood
Polycythemia vera
Transient erythroblastopenia of childhood
Primary myelofibrosis
Chronic neutrophilic leukemia
Drug-induced thrombocytopenic purpura
Aplastic anemia