Hydroxyurea: The drug of choice for polycythemia vera and essential thrombocythemia.

Hydroxyurea is an old drug that is often used to control essential thrombocythemia and polycythemia vera in patients with high-risk disease. It is usually well tolerated and cheap and has been proven effective in many studies for the prevention of thrombohemorrhagic complications associated with these disorders. However, many clinicians are reluctant to use it because of the perceived risk of progression to acute leukemia. Several recent, large studies have given this drug a new lease on life. Relevant results from these studies are discussed, and the risk of leukemia is placed in perspective to demonstrate that hydroxyurea remains the drug of choice in patients with either of these disorders.