The toxicity of hydroxyurea (HU), a treatment for specific neoplasms, sickle-cell disease, polycythemia vera and thrombocytosis was assessed in rats. Forty rats were divided equally into four groups. The first group was kept as control and received only purified water, the second group (HU250) orally administered hydroxyurea 250 mg/kg b.wt/day, the third group (HU500) administered hydroxyurea 500 mg/kg b.wt/day and the fourth group (HU750) administered hydroxyurea 750 mg/kg b.wt/day. The treatment was continued for 20 days. The evaluated parameters were assessed after 10 and 20 days of the experiment. Results revealed decrease in body weight in all treated groups. In addition, decreased circulating leukocytes, erythrocytes and platelets with decreased bone marrow cellularity were evident in all treated groups with different degree of severity. Moreover, aplastic anemia associated with marked severe hypocellularity of bone marrow was detected in HU500 and HU750 groups on the second period of the experiment. It could be concluded that hydroxyurea administration induced hematopoietic and bone marrow toxicity in rats.
hydroxyurea, bone marrow, aplastic anemia, hematology.