Hydroxykarbamid Medac (Hydroxycarbamide)

Hydroxycarbamide is used in several hematologic and oncologic conditions where it suppresses abnormal cell proliferation.

• Chronic myelogenous leukemia: reduces leukemic cell growth and improves hematologic parameters.
• Sickle cell disease: decreases frequency of painful crises and reduces need for transfusions.
• Essential thrombocythemia: lowers platelet counts and mitigates thrombotic risk.
• Polycythemia vera: controls red blood cell mass and helps maintain target hematocrit.
• Melanoma: used as part of combination therapy to inhibit tumor cell replication.

• Hydroxycarbamide inhibits the enzyme ribonucleotide reductase, which is essential for the conversion of ribonucleotides to deoxyribonucleotides. By limiting deoxyribonucleotide pools, the drug impairs DNA synthesis and repair, leading to cell cycle arrest primarily in the S phase. This antiproliferative effect preferentially targets rapidly dividing malignant and abnormal hematopoietic cells. The reduction in DNA replication triggers apoptosis in susceptible clones and modulates the bone marrow microenvironment, contributing to clinical benefit in myeloproliferative diseases.

Hydroxycarbamide may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea or vomiting: gastrointestinal discomfort often occurring early in therapy.
• Fatigue or weakness: general tiredness that may affect daily activities.
• Myelosuppression: reduced white blood cells, red blood cells or platelets leading to anemia or increased infection risk.
• Skin changes: hyperpigmentation or rash.

Serious or Rare Side Effects

• Severe neutropenia: marked drop in neutrophils increasing infection susceptibility.
• Acute myeloid leukemia: rare transformation to a secondary malignancy.
• Pulmonary toxicity: interstitial lung disease or fibrosis presenting with cough and dyspnea.

When prescribing hydroxycarbamide, clinicians should observe several precautionary measures to ensure patient safety.

• Baseline blood counts: obtain complete blood count before initiation and monitor regularly.
• Renal function: assess kidney function and adjust dose in impairment.
• Hepatic function: monitor liver enzymes due to potential hepatotoxicity.
• Pregnancy and lactation: avoid use unless benefits outweigh risks; discuss with specialist.
• Drug interactions: review concomitant medications that may enhance myelosuppression.
• Store at ambient temperature: keep below 25 °C in original packaging, protect from moisture.

Hydroxycarbamide interacts with several agents that can alter its efficacy or toxicity.

Major Interactions (Avoid)

• Allopurinol: may increase hydroxycarbamide toxicity; avoid co‑administration.
• Anticoagulants (warfarin): heightened risk of bleeding; avoid combined use.
• Live vaccines: immunosuppression can reduce vaccine effectiveness; avoid.

Moderate Interactions (Monitor Closely)

• Antiretroviral drugs (e.g., zidovudine): may enhance myelosuppression; monitor blood counts.
• NSAIDs: increased risk of gastrointestinal irritation; observe for symptoms.
• Phenytoin: may reduce hydroxycarbamide plasma levels; adjust dosage if needed.