It is an antimetabolite indicated for the treatment of: x Resistant chronic myeloid leukemia. x Locally advanced squamous cell carcinomas of the head and neck, (excluding lip) in combination with concurrent chemoradiation.
Hydroxyurea is converted to a free radical nitroxide (NO) in vivo, and transported by diffusion into cells where it quenches the tyrosyl free radical at the active site of the M2 protein subunit of ribonucleotide reductase, inactivating the enzyme. The entire replicase complex, including ribonucleotide reductase, is inactivated and DNA synthesis is selectively inhibited, producing cell death in S phase and synchronization of the fraction of cells that survive. Repair of DNA damaged by chemicals or irradiation is also inhibited by hydroxyurea, offering potential synergy between hydroxyurea and radiation or alkylating agents. Hydroxyurea also increases the level of fetal hemoglobin, leading to a reduction in the incidence of vasoocclusive crises in sickle cell anemia. Levels of fetal hemoglobin increase in response to activation of soluble guanylyl cyclase (sGC) by hydroxyurea-derived NO.
Individualize treatment based on tumor type,disease state,response to treatment,patient risk factors,and current clinical practice standards. x Renal impairment: Reduce the dose of It by 50% in patients with creatinine clearance less than 60 mL/min.
Hydroxyurea can enhance toxicity when used alongside antiretroviral drugs and may also interfere with laboratory tests measuring uric acid, urea, or lactic acid levels.
In patients who have demonstrated a previous hypersensitivity to hydroxyurea or any other component of its formulation. x Myelosuppression: Do not give if bone marrow function is markedly depressed. Monitor hematology labs and interrupt,reduce dose as appropriate. x Malignancies: Advise protection from sun exposure and monitor for secondary malignancies. x Embryo-Fetal toxicity: Can cause fetal harm. Advise of potential risk to a fetus and use of effective contraception. x Vasculitic toxicities: Discontinue It and initiate treatment if this occurs. x Live Vaccinations: Avoid live vaccine use in a patient taking It. x Risks with concomitant use of antiretroviral drugs: Pancreatitis, hepatotoxicity,and neuropathy have occurred. Monitor for signs and symptoms in patients with HIV infection using antiretroviral drugs; discontinue It,and implement treatment. x Radiation recall: Monitor for skin erythema in patients who previously received radiation and manage symptomatically.
hematological,gastrointestinal symptoms,and anorexia.
Lactation Hydroxyurea is excreted in human milk. Discontinue breastfeeding during treatment with it.
Acute mucocutaneous toxicity has been reported in patients receiving hydroxyurea at dosages several times the therapeutic dose. Soreness, violet erythema, edema on palms and soles followed by scaling of hands and feet, severe generalized hyperpigmentation of the skin, and stomatitis have also been observed.
Store at or below 25°C, in a cool and dry place. Keep away from light. Keep out of the reach of children.
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