Leuject (Cladribine)

Cladribine is indicated for diseases where selective lymphocyte depletion is therapeutic, particularly in hematologic malignancies and certain autoimmune disorders.

• Hairy cell leukemia: reduces malignant B‑cell proliferation and induces durable remission.
• Chronic lymphocytic leukemia (B‑cell): decreases circulating malignant lymphocytes and improves disease control.
• Relapsing forms of multiple sclerosis: lowers relapse rate by modulating immune activity.

• Cladribine is a purine nucleoside analog that is phosphorylated inside cells to its active triphosphate form. The metabolite incorporates into DNA during replication, causing strand breaks and inhibiting DNA synthesis, which triggers apoptosis of proliferating B and T lymphocytes, resulting in selective immunosuppression and antitumor activity.

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

Common Side Effects

• Lymphopenia: reduced lymphocyte counts leading to increased infection risk.
• Neutropenia: low neutrophil levels causing susceptibility to bacterial infections.
• Fatigue: persistent tiredness affecting daily activities.
• Nausea: mild to moderate gastrointestinal discomfort.
• Fever: transient elevations in body temperature.
• Headache: occasional mild to moderate pain.

Serious or Rare Side Effects

• Opportunistic infections: severe infections such as pneumocystis pneumonia.
• Severe lymphopenia: profound immune suppression requiring medical intervention.
• Autoimmune hepatitis: liver inflammation with potential for hepatic failure.
• Secondary malignancies: rare development of new cancers.
• Anaphylactic reactions: acute hypersensitivity requiring emergency care.
• Progressive multifocal leukoencephalopathy (PML): rare demyelinating disease of the brain.

When using Cladribine, careful monitoring and specific precautions are recommended to minimize risks.

• Monitor blood counts: perform regular complete blood count tests to detect cytopenias.
• Screen for infections: evaluate for active infections before initiating therapy.
• Avoid live vaccines: live attenuated vaccines may cause disease during immunosuppression.
• Pregnancy counseling: discuss potential fetal risks with a healthcare professional.
• Specialist supervision: treatment should be managed by an experienced hematologist or neurologist.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Cladribine can interact with other medicines, affecting its safety and efficacy.

Major Interactions (Avoid)

• Live vaccines: increased risk of vaccine‑derived infection.
• Concurrent immunosuppressants (e.g., azathioprine): additive bone‑marrow suppression.
• Antiviral agents (e.g., ganciclovir): heightened myelosuppressive effect.
• Chemotherapy agents (e.g., cyclophosphamide): overlapping toxicity on blood cells.
• High‑dose steroids: may amplify immunosuppression.

Moderate Interactions (Monitor Closely)

• CYP450 inhibitors (e.g., fluconazole): possible increased cladribine exposure.
• CYP450 inducers (e.g., rifampicin): potential reduction in drug levels.
• Inactivated vaccines: monitor immune response efficacy.
• Antibiotics (e.g., trimethoprim‑sulfamethoxazole): may mask infection signs.
• Antifungal agents (e.g., voriconazole): may affect metabolism.