Hydrea (Hydroxycarbamide)

Hydrea is indicated for several chronic blood disorders and selected solid tumors, where it helps control abnormal cell proliferation.

• Chronic myeloid leukemia (CML) in patients who have not responded adequately to other therapies.
• Polycythemia vera to reduce elevated red blood cell mass and lower risk of thrombosis.
• Essential thrombocythemia for managing high platelet counts and preventing thrombotic events.
• Sickle cell disease to increase fetal hemoglobin levels and reduce vaso‑occlusive crises.
• Melanoma as part of combination chemotherapy regimens in certain clinical settings.

• Hydroxycarbamide inhibits the enzyme ribonucleotide reductase, the key catalyst for converting ribonucleotides to deoxyribonucleotides. By limiting the intracellular pool of deoxyribonucleotides, DNA synthesis is slowed, leading to reduced replication of rapidly dividing cells such as malignant leukocytes and erythroid precursors. The resulting cytostatic effect contributes to disease control in hematologic malignancies and to increased fetal hemoglobin production in sickle cell disease.

Hydrea may cause a range of adverse reactions, which are generally categorized by frequency and severity.

Common

• Nausea, vomiting, or loss of appetite.
• Mild to moderate bone marrow suppression leading to anemia, neutropenia, or thrombocytopenia.
• Skin changes such as hyperpigmentation or rash.
• Elevated liver enzymes indicating hepatic irritation.

Serious

• Severe bone marrow failure with pancytopenia.
• Acute renal impairment or nephrotoxicity.
• Life‑threatening infections due to profound neutropenia.
• Pulmonary toxicity, including interstitial pneumonitis.

Before starting Hydrea, clinicians should evaluate several safety considerations to minimize risk.

• Perform baseline complete blood count and liver function tests.
• Monitor blood counts regularly during therapy to detect marrow suppression early.
• Use caution in patients with pre‑existing renal or hepatic impairment.
• Avoid use during pregnancy; the drug is classified as pregnancy category D.
• Counsel women of child‑bearing potential about effective contraception throughout treatment and for a defined period after discontinuation.
• Assess for history of hypersensitivity to hydroxyurea or related compounds.

Hydrea can interact with other medicines, affecting its efficacy or increasing toxicity.

Avoid

• Concurrent use of other myelosuppressive agents (e.g., chemotherapy, azathioprine) that may exacerbate bone marrow depression.
• Strong CYP2C9 inhibitors that could increase hydroxycarbamide plasma levels.
• Live vaccines, because immunosuppression may reduce vaccine effectiveness and increase infection risk.

Use with caution

• Allopurinol, which may enhance hematologic toxicity.
• NSAIDs or aspirin, which can increase the risk of gastrointestinal bleeding.
• Antiretroviral drugs such as zidovudine, which may have additive bone marrow effects.