WARNING

Treatment of patients with DROXIA may be complicated by severe, sometimes lifethreatening, adverse effects. DROXIA should be administered under the supervision of a physician experienced in the use of this medication for the treatment of sickle cell anemia.

Hydroxyurea is mutagenic and clastogenic, and causes cellular transformation to a tumorigenic phenotype. Hydroxyurea is thus unequivocally genotoxic and a presumed transspecies carcinogen which implies a carcinogenic risk to humans. In patients receiving long-term hydroxyurea for myeloproliferative disorders, such as polycythemia vera and thrombocythemia, secondary leukemias have been reported. It is unknown whether this leukemogenic effect is secondary to hydroxyurea or is associated with the patient's underlying disease. The physician and patient must very carefully consider the potential benefits of DROXIA relative to the undefined risk of developing secondary malignancies.