Hydrea

Hydrea, the brand name for hydroxyurea, is an antineoplastic medication used to treat several hematologic disorders and certain cancers. It acts as a ribonucleotide reductase inhibitor, reducing the pool of deoxynucleotides and thereby inhibiting DNA synthesis in rapidly dividing cells.

Common medical uses include cytoreduction in myeloproliferative disorders such as polycythemia vera, essential thrombocythemia, and myelofibrosis, as well as treatment of certain leukemias and solid tumors in combination regimens. It is also prescribed for adults with sickle cell disease to reduce the frequency of painful crises and acute chest syndrome; indications vary by country and regulatory approval.

Mechanism of action: by inhibiting ribonucleotide reductase, hydroxyurea decreases DNA synthesis, preferentially affecting proliferating cells.

Administration and dosing: hydroxyurea is administered orally as capsules, usually once daily, with dose adjusted to body size, diagnosis, and blood counts. Treatment requires regular laboratory monitoring, including complete blood counts and liver and kidney function.

Safety and adverse effects: the most common adverse effects are bone marrow suppression (anemia, leukopenia, thrombocytopenia), nausea, vomiting, diarrhea, mucositis, rash, and hair changes. Teratogenicity necessitates contraception during treatment and for a period after. It can cause liver or kidney function abnormalities; risk of infection increases with neutropenia. Long-term use has been associated with secondary malignancies in some settings.