Oribamide (Hydroxycarbamide)

Oribamide is an antineoplastic agent that acts on abnormal hematologic cells.

• Sickle cell disease: reduces the frequency of painful vaso‑occlusive crises.
• Chronic myelogenous leukemia: helps to control the proliferation of leukemic cells.
• Polycythemia vera: lowers the elevated red‑cell mass and hematocrit.
• Essential thrombocythemia: decreases the platelet count.
• Myelodysplastic syndromes : provides symptomatic relief of cytopenia and reduces need for transfusions.

• Hydroxycarbamide inhibits ribonucleotide reductase, the enzyme responsible for converting ribonucleotides to deoxyribonucleotides. This blockade reduces the intracellular pool of deoxyribonucleotides needed for DNA synthesis, thereby slowing DNA replication and limiting the proliferation of rapidly dividing cells, particularly abnormal hematopoietic cells.

Hydroxycarbamide may cause a range of adverse reactions.

Common Side Effects

• Nausea or vomiting
• Mild gastrointestinal discomfort
• Transient skin discoloration (hyperpigmentation)
• Low white‑blood‑cell count (leukopenia)
• Mild fatigue
• Elevated liver enzymes

Serious or Rare Side Effects

• Severe neutropenia or agranulocytosis
• Acute myeloid leukemia transformation
• Severe renal impairment
• Life‑threatening hypersensitivity reactions
• Pulmonary toxicity (interstitial pneumonitis)
• Significant hemorrhage due to thrombocytopenia

When prescribing Hydroxycarbamide, clinicians should consider several safety measures.

• Monitor blood counts: regular CBCs are required to detect cytopenias early.
• Assess renal function: dose adjustments may be needed in renal impairment.
• Evaluate hepatic function: liver enzymes should be checked periodically.
• Avoid use in patients with known hypersensitivity to hydroxycarbamide.
• Store at below 25°C: keep in the original packaging ; protect from moisture.

Hydoxycarbamide can interact with several medicines, requiring vigilance.

Major Interactions (Avoid)

• Allopurinol: may increase hydroxycarbamide toxicity.
• Live‑Vaccines : risk of infection due to immunosuppression.
• Antiretroviral drugs (e.g., zid ").

Moderate ...