What is hydrea (hydroxyurea) usually used to treat?

Many diseases. This antimetabolite has been used for >100yrs in treating benign & malignant conditions including sickle cell disease, essential thrombocytosis, p. Vera, cml, prostate cancer, psoriasis, & even aids.
Tumors. Hydrea (hydroxyurea) has been used to treat certain cancers such as melanoma, chronic myelocytic leukemia, and some head and neck tumors. It has also been used in patients with sickle cell anemia.