Busulfan is a cell cycle-nonspecific alkylating agent that interferes with DNA replication and the transcription of RNA, resulting in the disruption of nucleic acid functioning.

♦ Chronic myelogenous leukemia: less effective in patients who lack the Philadelphia chromosome. Has been found to induce remission in 80% to 90% of patients treated. Not effective in patients in the blastic phase.

♦ Other uses: severe thrombocytopenia and polycythemia vera. Also used in the marrow-ablating regimen before bone marrow transplantation for the treatment of malignant and nonmalignant conditions.

Extensively metabolized and slowly excreted in the urine. Crosses the placental barrier. Half-life: unknown.

♦ For induction of remission: Usual adult dose is 4 to 8 mg/day, but doses of 1 to 12 mg/day have been used. Dosing is on a weight basis according to the manufacturer; dosing is the same for adults and children, with recommended daily doses of about 0.06 mg/kg or 1.8 mg/m². Continue until the leukocyte count drops to about 15,000/mm³. Patients in remission should be seen monthly. Treatment should be resumed when the leukocyte count reaches 50,000/mm³.