Hidroxicarbamida Generis (Hydroxycarbamide)

Hydroxycarbamide is indicated for several hematologic disorders where reduction of abnormal blood cell production is required.

• Sickle cell disease: reduces frequency of painful vaso‑occlusive crises.
• Chronic myelogenous leukemia (CML): used as part of disease‑modifying therapy.
• Polycythemia vera: helps control elevated red blood cell mass.
• Essential thrombocythemia: lowers platelet counts to target levels.
• Occasionally prescribed for other myeloproliferative neoplasms under specialist supervision.

• Hydroxycarbamide inhibits the enzyme ribonucleotide reductase, which is essential for converting ribonucleotides to deoxyribonucleotides. By limiting deoxyribonucleotide pools, the drug impairs DNA synthesis and cell replication, particularly affecting rapidly dividing hematopoietic cells. This antimetabolite action leads to decreased production of abnormal blood cells and modulation of marrow activity.

Adverse reactions to hydroxycarbamide vary in frequency and severity.

Common

• Nausea or vomiting
• Mild gastrointestinal upset
• Temporary hair thinning

Serious

• Severe bone marrow suppression (neutropenia, thrombocytopenia)
• Acute renal failure
• Life‑threatening infections due to immunosuppression

Hydroxycarbamide requires careful monitoring and specific precautions to minimize risks.

• Baseline and periodic complete blood counts to detect marrow suppression.
• Renal and hepatic function tests before initiation and during therapy.
• Avoid use in pregnancy; it is classified as Category D and may cause fetal harm.
• Counsel women of childbearing potential about effective contraception.
• Monitor for signs of infection or bleeding, especially in immunocompromised patients.
• Adjust dose in patients with impaired kidney function.
• Discontinue promptly if severe toxicity develops.

Hydroxycarbamide can interact with several medicines, affecting its efficacy or safety.

Avoid

• Concurrent use with strong CYP2C9 inhibitors (e.g., fluconazole) that may increase hydroxycarbamide levels.
• Co‑administration with other myelosuppressive agents (e.g., azathioprine) that can exacerbate bone‑marrow toxicity.
• Combining with nephrotoxic drugs (e.g., aminoglycosides) that raise risk of renal impairment.

Use with caution

• Anticoagulants (e.g., warfarin) – monitor coagulation parameters.
• Allopurinol – may increase risk of hypersensitivity reactions.
• Live vaccines – reduced immune response may occur.
• NSAIDs – may increase risk of gastrointestinal irritation.