Hydroxyurea is used most commonly for patients with chronicmyelogenous leukemia.
Hydroxyurea is also used for solid tumors and head and neck cancer.
Hydroxyurea is readily absorbed and well distributed into CSF af-ter oral administration. It reaches a peak serum level 2 hours after administration.
About one-half of the dose is metabolized by the liver to carbon dioxide, which is excreted by the lungs, or to urea, which is ex-creted by the kidneys. The remaining one-half is excreted un-changed in urine.
Hydroxyurea exerts its effect by inhibiting the enzyme ribonu-cleotide reductase, which is necessary for DNA synthesis.
Hydroxyurea kills cells in the S phase of the cell cycle and holds other cells in the G1 phase, where they’re most susceptible to irra-diation.
Hydroxyurea is used to treat selected myeloproliferative disor-ders. It may produce temporary remissions in some patients with metastatic malignant melanomas as well.
Hydroxyurea is also used in combination therapy with radiation to treat cancers of the head, neck, and lungs.
Cytotoxic drugs and radiation therapy enhance the toxicity of hy-droxyurea. (See Adverse reactions to hydroxyurea.)