Myleran (Busulfan)

Busulfan is an alkylating antineoplastic agent used in specific hematologic malignancies and transplant conditioning.

• Chronic myeloid leukemia: reduces leukemic cell proliferation and helps achieve disease control.
• Bone marrow transplantation conditioning: eradicates residual malignant cells and creates immunosuppression to facilitate engraftment.
• Acute myeloid leukemia (conditioning): contributes to myeloablation before stem‑cell infusion.

• Busulfan alkylates DNA by forming covalent cross‑links between DNA strands, which blocks DNA replication and transcription. This interference triggers apoptosis in rapidly dividing cells, particularly malignant hematopoietic progenitors, leading to cell death and myeloablation required for transplant conditioning.

Busulfan may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Nausea and vomiting: gastrointestinal upset commonly reported during therapy.
• Mucositis: inflammation and ulceration of the oral mucosa.
• Alopecia: reversible hair loss affecting scalp and body hair.
• Skin rash: mild erythematous eruptions.

Serious or Rare Side Effects

• Hepatic veno‑occlusive disease: potentially life‑threatening liver injury.
• Pulmonary fibrosis: progressive scarring of lung tissue.
• Seizures: central nervous system toxicity, especially at high plasma levels.
• Severe bone‑marrow suppression: profound neutropenia, anemia, and thrombocytopenia increasing infection and bleeding risk.

Before initiating Busulfan therapy, several safety considerations are recommended.

• Dose adjustment: monitor complete blood counts and liver function tests regularly.
• Organ function: assess hepatic and renal function to determine suitability.
• Drug interactions: avoid concomitant use with agents that markedly increase myelosuppression.
• Pregnancy and lactation: contraindicated unless benefits clearly outweigh potential risks.
• Store at ambient temperature: keep below 25°C in the original packaging, protect from moisture.

Busulfan can interact with several medicines, requiring careful management.

Major Interactions (Avoid)

• Azathioprine: additive myelosuppression may be severe.
• Cyclophosphamide: combined bone‑marrow toxicity increases risk of pancytopenia.
• Chloramphenicol: impaired metabolism can raise Busulfan plasma concentrations.

Moderate Interactions (Monitor Closely)

• Phenytoin: may reduce Busulfan exposure, potentially compromising efficacy.
• Antifungal azoles (e.g., fluconazole): can increase Busulfan levels, necessitating therapeutic drug monitoring.