Drug Groups

approved; investigational

Description

An alkylating agent having a selective immunosuppressive effect on bone marrow. It has been used in the palliative treatment of chronic myeloid leukemia (myeloid leukemia, chronic), but although symptomatic relief is provided, no permanent remission is brought about. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), busulfan is listed as a known carcinogen. [PubChem]

Indication

For use in combination with cyclophosphamide as a conditioning regimen prior to allogeneic hematopoietic progenitor cell transplantation for chronic myelogenous leukemia (FDA has designated busulfan as an orphan drug for this use). Also used as a component of pretransplant conditioning regimens in patients undergoing bone marrow transplantation for acute myeloid leukemia and nonmalignant diseases.

Pharmacology

Busulfan is an antineoplastic in the class of alkylating agents and is used to treat various forms of cancer. Alkylating agents are so named because of their ability to add alkyl groups to many electronegative groups under conditions present in cells. They stop tumor growth by cross-linking guanine bases in DNA double-helix strands - directly attacking DNA. This makes the strands unable to uncoil and separate. As this is necessary in DNA replication, the cells can no longer divide. In addition, these drugs add methyl or other alkyl groups onto molecules where they do not belong which in turn leads to a miscoding of DNA. Alkylating agents are cell cycle-nonspecific and work by three different mechanisms, all of which achieve the same end result - disruption of DNA function and cell death.

Toxicity

Signs of overdose include allergic reaction, unusual bleeding or bruising, sudden weakness or unusual fatigue, persistent cough, congestion, or shortness of breath; flank, stomach or joint pain; pronounced nausea, vomiting, diarrhea, dizziness, confusion, or darkening of the skin, chills, fever, collapse, and loss of consciousness.

Affected Organisms

Biotransformation

Mainly Hepatic. Busulfan is predominantly metabolized by conjugation with glutathione, both spontaneously and by glutathione S-transferase (GST) catalysis.

Absorption

Completely absorbed from the gastrointestinal tract.

Half Life

2.5 hours

Protein Binding

32.4%

Elimination

Following administration of 14C- labeled busulfan to humans, approximately 30% of the radioactivity was excreted into the urine over 48 hours; negligible amounts were recovered in feces.

Clearance

* 2.52 ml/min/kg [Following an infusion of dose of 0.8 mg/kg every six hours, for a total of 16 doses over four days]

References

External Links