Chemotherapy and Drug Therapy
Chemotherapy and drug therapy is used for essential thrombocythemia (ET) to lower your platelet count. Your doctor may use one or more of the following drugs:
Hydroxyurea (Hydrea®). This myelosuppressive drug (an agent that suppresses the marrow's production of blood cells), a chemotherapeutic agent, can be used as initial therapy for ET. Hydroxyurea, given by mouth, is often successful in decreasing the platelet count within several weeks, with few short-term side effects. In some patients it may lower red blood cells, causing anemia; other rare side effects are mouth ulcers, change in the sense of taste, skin ulcers or rash. There is some controversial evidence that hydroxyurea is associated with an increased risk of developing acute leukemia after long-term therapy and is frequently avoided as therapy for younger patients. However, it is thought to have much less potential for causing leukemia than other myelosuppressive agents, such as radiophosphorus, and alkylating agents, such as melphalan (Alkeran®), chlorambucil (Leukeran®) and others.
Anagrelide (Agrylin®). This is a non cytotoxic drug (an agent that does not kill cells) that effectively decreases platelet formation in most patients and is given by mouth. It has not been associated with increased risk for leukemia and is a therapy alternative to other treatments, such as hydroxyurea. Side effects of anagrelide can occur, including fluid retention, heart and blood pressure problems, headaches, dizziness, nausea and diarrhea.
Interferon alfa (Intron® A, Roferan-A®). Another treatment for lowering platelet counts in patients with ET. However, it is not used in most patients because, in comparison with other treatments for ET, it is less convenient to administer-it is given by intramuscular or subcutaneous injection-and may cause troublesome side effects. Some patients experience moderately severe flu like symptoms, confusion, depression or other complications. Development of sustained-release preparations provides a new option for patients; injections would be weekly, a regimen patients tend to tolerate better (particularly in the case of Pegasys).
Aspirin therapy. Aspirin, given by mouth, is effective for patients at high risk for clotting complications and is commonly prescribed. In patients with low risk for clotting, evidence for its use is less strong. It may also increase bleeding risk in patients with extremely high platelets. For these reasons, the use of aspirin in treating ET needs to be individualized. Pregnant patients may be treated with low-dose aspirin to reduce the risk of miscarriage, fetal growth retardation, premature delivery or other complications. Aspirin should be avoided for at least one week prior to delivery to reduce any risk of bleeding complications in the mother or the newborn.
If you would like to read about these drugs individually, including information about side effects, click here.