Drug information of Busulfan

Busulfan

Drug group:

Busulfan is used treat a certain type of chronic myelogenous leukemia (CML; a type of cancer of the white blood cells). Busulfan is in a class of medications called alkylating agents. It works by slowing or stopping the growth of cancer cells in your body.

Mechanism of effect

Alkylating agent ; interferes with DNA eplication and RNA transcription; cross-links DNA strands; has little immunosuppressive activity; affects myeloid cells more than lymphoid cells; very toxic to hematopoietic stem cells

Pharmacodynamic

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.

Pharmacokinetics

• Half-life elimination: 2.5 hr
• Onset: 1-2 wk
• Duration: 24 hr
• Time to peak serum: 1hr (PO); 5 min (IV)
• Bioavailability: 68-80% depending on age
• Protein Bound: 32%
• Vd: 0.6-1.0 L/kg (adults); 1.4-1.6 L/kg (children)
• Metabolism: Liver
• Metabolites: Methanesulfonic acid & 3-hydroxytetrahydrothiophene-1,1-dioxide
• Clearance: 2.52 mL/min/kg
• Excretion: Urine (25-60%)
• Dialyzable: Yes

Dosage

Chronic Myelogenous Leukemia
Initial dose: 60 mcg/kg or 1.8 mg/m2 orally once a day. The usual dosage range for remission induction is 4 to 8 mg/day.
Bone Marrow Transplantation
2 to 4 mg/kg (up to 560 mg) orally every 6 hours for 4 days. High dose cyclophosphamide has been used in combination with busulfan to prepare patients for bone marrow transplantation. Doses are administered every 6 hours as 2 hour infusions over 4 days for a total of 16 doses.

Alerts

• Bone marrow suppression is a common occurrence; reduce dose or discontinue oral administration for unusual suppression (bone marrow biopsy may be necessary); hematopoietic progenitor cell transplantation is required to prevent potentially fatal complications of prolonged myelosuppression
• Monitoring is very important after administering these doses
• This drug should be administered under the supervision of an experienced cancer chemotherapy physician.
• Seizures reported with use; initiate anticonvulsant prophylactic therapy prior to treatment with busulfan ; monitor patients with history of seizure disorder, head trauma or receiving epileptogenic drugs
• Cardiac temponade reported in children with thalassemia in combination with cyclophosphamide
• Ovarian failure may occur

Points of recommendation

• Administration: take on empty stomach to decrease risk of N/V
• Monitor: CBC, Hgb, LFTs
• It is given as an infusion into a vein over a period of time.
• Other drugs may be given before busulfan injection to help avoid side effects.
• Talk with your doctor before getting any vaccines. Use with this medicine may either raise the chance of an infection or make the vaccine not work as well.
• You may bleed more easily. Be careful and avoid injury. Use a soft toothbrush and an electric razor.
• You may have more chance of getting an infection. Wash hands often. Stay away from people with infections, colds, or flu.
• If you are a man and have sex with a female who could get pregnant, protect her from pregnancy during care and for some time after care ends. Use birth control that you can trust. Talk with your doctor to see how long to use birth control after you stop this medicine.
• Tell your doctor right away if you notice any symptoms of cancer, including unusual lumps, sudden weight loss.

Pregnancy level

D


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